Ruling on what is known as “khatam shifa”, and praying behind an innovator and calling him (to the right path)
Question

                My bother just had an operation and his situation is critical. So, what my mom decided to do is perform khatam shifa which is basically saying ya salaamu 12500 times, reading some dua, reading Surah Yaseen and Surah Ar-Rahman 40 times each, feeding the poor and giving away goats. Is is something from our Rasul Sallallahu Alayhi Wasallam.

Another question is regarding the mosques in Bangladesh. They do a lot of bidah that includes asking wasillah, teaching acts mentioned above, celebrate milad in nabi and I can keep going on for ages. Is it permissible to pray behind those imams who teaches such things? 
Sometimes, when I try to talk to them, whether they get angry and they do not reason and give sahih daleel to their arguments. They always say that some alims taught them and they are better than us and we should follow them without question. We are facing this diellma to either be quiet and allow them to follow what they will. 

Sometimes it ends in quarrel and at times ruins relationships/friendship.... because as much as we try they always say that the alim is far better and knows what he is preaching.

Finally, what should I do to explain my family and friends?.
Praise be to Allah.
    Firstly: 

    With regard to what is called “khatam shifa”, it is an 
    innovation (bid‘ah). The Prophet (blessings and peace of Allah be upon him) 
    said: “The worst of matters are those which are newly invented (in 
    religion). Every newly invented matter is an innovation, every innovation is 
    a going astray, and every going astray is in the Fire.” With regard to these 
    soorahs and adhkaar (dhikrs) that are mentioned in the question, this is 
    something for which there is no evidence (daleel), and it is not permissible 
    to do these things for which there is no evidence in the Book of our Lord or 
    the Sunnah of our Prophet (blessings and peace of Allah be upon him). 

    What is prescribed in our religion is to offer supplication 
    (du‘aa’) for the sick person and to ask Allah to heal him and purify him. 
    That will have the greatest impact in taking away the disease and bringing 
    about rapid healing. It was narrated from Ibn ‘Abbaas (may Allah be pleased 
    with him) that the Prophet (blessings and peace of Allah be upon him) said: 
    “Whoever visits a sick person whose time (of death) has not yet come, and 
    says to him seven times ‘As’al Allah al-‘Azeem Rabb al-‘Arsh al-‘Azeem an 
    yashfeeyaka (I ask Allah the Almighty, Lord of the Mighty Throne, to 
    heal you)’, Allah will heal him of that sickness.”

    Narrated by Ahmad (2137), Abu Dawood (3106) and at-Tirmidhi 
    (2083); classed as saheeh by al-Albaani. 

    So you should offer supplication (du‘aa’) for him in the 
    wording mentioned in this hadeeth and other saheeh hadeeths. 

    The same applies to giving charity. There is no doubt that 
    spending for the sake of Allah is something that brings good. It was 
    narrated from Abu Hurayrah (may Allah be pleased with him) that the Prophet 
    (blessings and peace of Allah be upon him) said: 
    “There is no day on which people wake up, but two angels come down and one 
    of them says: ‘O Allaah, give more to the one who spends,’ and the other 
    says, ‘O Allaah, send destruction upon the one who withholds.’”

    Narrated by al-Bukhaari (1442) and Muslim (1010).

    So spend and give charity, and be optimistic about 
    compensation from Allah, may He be glorified. 

    Secondly: 

    With regard to praying behind an innovator, Shaykh al-Islam 
    [Ibn Taymiyah] said in Majmoo‘ al-Fataawa (23/355): 

    With regard to praying behind an innovator, this is a matter 
    concerning which there is a difference of opinion and it is subject to 
    further discussion. If you cannot find any other imam apart from him, such 
    as in the case of Jumu‘ah prayer which is only held in one place, or Eid 
    prayer, or prayers during Hajj behind the imam who is in charge of Hajj, 
    these prayers are to be offered behind anyone, whether he is righteous or 
    otherwise, according to the consensus of Ahl as-Sunnah wa’l-Jamaa‘ah. Rather 
    the ones who refrain from offering these prayers behind the imams are the 
    followers of innovations such as the Raafidis and others like them, who do 
    not attend any Jumu‘ah prayer or prayer in congregation. If there is only 
    one mosque in the village, then praying in congregation behind an immoral 
    person is better than praying on one’s own at home, lest that lead to giving 
    up prayer in congregation altogether. But if it is possible to pray behind 
    someone other than the innovator, that is undoubtedly better and preferable. 
    But if he prays behind him, there is a scholarly difference of opinion 
    concerning his prayer. The view of ash-Shaafa‘i and Abu Haneefah is that his 
    prayer is valid; however in the madhhabs of Maalik and Ahmad there is a 
    dispute concerning this issue and it is subject to further discussion. 

    However this only applies to bid‘ah that is known to be 
    contrary to the Qur’an and Sunnah, such as the innovations of the Raafidis, 
    Jahamis and so on. People argue about many issue of religion in this 
    country, and both parties to an argument may innovators, and both of them 
    may be ignorant and misinterpreting things, so the refusal of one of them to 
    pray behind the other is not better than if it is the other way round. But 
    once the Sunnah is established and becomes known, and one person or group 
    goes against it, this is the matter concerning which there is a difference 
    of scholarly opinion. And Allah knows best. End quote. 

    In Fataawa al-Lajnah ad-Daa’imah (7/364) there is the 
    following question: 

    Is it permissible to pray behind an imam who is an 
    innovator? 

    The committee replied: 

    Whoever can find an imam who is not an innovator should pray 
    behind him and not behind the innovator. Whoever cannot find anyone except 
    this innovator should advise him in the hope that he will give up his 
    innovation. If he does not accept that advice, and his innovation involves 
    shirk, such as those who seek the help of the dead or call upon them instead 
    of Allah, or offer sacrifices to them, then he (the one who offered advice) 
    should not pray behind him because he is a kaafir and his prayer is invalid, 
    and it is not right to appoint him as an imam. If his innovation does not 
    make him a kaafir, such as uttering the intention out loud, his prayer is 
    valid as is the prayer of those who pray behind him. End quote. 

    With regard to calling these people (da‘wah) and advising 
    them, seek the help of Allah first and foremost, make your intention sincere 
    and intend to guide them to the right path, and Allah will help you in 
    that. 

    You should explain to them that they are going against the 
    teachings of Islam, with evidence and proof, and demonstrate that the 
    specious argument they follow is wrong; you should also refer to scholars 
    concerning issues that you are uncertain about, so that their specious 
    arguments will not affect you and they will not defeat you in argument, lest 
    the ignorant think that their view is correct. And you should pay attention 
    to being kind and gentle in all of that. 

    And Allah knows best.