He is going to travel and will remain abroad for three months; does he have to fast Ramadan?
Question

                I am going to travel, by Allah’s leave, to Milan in Italy for my work, to complete the company’s new project. That will take a long time, as long as three months, and the blessed month of Ramadan will come whilst I am there. My question is: do I have to fast? If I do not fast, what do I have to do to make it up?.
Praise be to Allah.
    If a person travels to a place and decides to stay there for 
    more than four days, then he comes under the same rulings as a resident 
    according to the majority of scholars among the Maalikis, Shaafa’is and 
    Hanbalis. So he comes under the same obligations as a resident with regard 
    to fasting and offering prayers in full. 

    It says in Fataawa al-Lajnah al-Daa’imah (8/99):

    Travel in which the concessions for the traveller are 
    prescribed is that which is customarily regarded as travel, and the distance 
    concerned is approximately 80 km. If a person travels this distance or more, 
    he may avail himself of the concessions of travel, such as wiping over the 
    socks for three days and nights, joining and shortening prayers and not 
    fasting in Ramadan. If the traveller intends to stay in the city for more 
    than four days, then he is not entitled to the concessions of travel, but if 
    he intends to stay for four days or less, then he may avail himself of those 
    concessions. The traveller who is staying in the city but does not know when 
    his stay there will end and has not set a specific time limit for his stay 
    there may avail himself of the concessions of travel even if that is for a 
    long period. There is no differentiation between travel by land or sea. End 
    quote. 

    Based on that, what you have to do is fast Ramadan and offer 
    prayers in full during this period, unless you are travelling from city to 
    city and the distance between them is 80 km or more, in which case it is 
    permissible for you not to fast whilst travelling, and it is also 
    permissible for you to join and shorten prayers. 

    And Allah knows best.