His parents refuse to let him shorten his lower garments. Should he obey them?
Question

My parents won’t let me shorten my lower garments (so that they do not come down below my ankles). Should I obey them or not?.
Praise be to Allah.Allah has commanded us to honour our parents in many places in His Book, such as when He says (interpretation of the meaning): 
“And We have enjoined on man to be good and dutiful to his parents; but if they strive to make you join with Me (in worship) anything (as a partner) of which you have no knowledge, then obey them not. Unto Me is your return and I shall tell you what you used to do”
[al-‘Ankaboot 29:8]
The greatest of rights are the rights of Allah, after which come the rights of created beings, foremost among which are the rights of parents. Hence Allah mentions His rights and parents’ rights together in many verses of the Holy Qur’aan, such as when He says (interpretation of the meaning): 
“And your Lord has decreed that you worship none but Him. And that you be dutiful to your parents. If one of them or both of them attain old age in your life, say not to them a word of disrespect, nor shout at them but address them in terms of honour.”
[al-Isra’ 17:23] 
Obeying parents is obligatory unless they enjoin sin, in which case they should not be obeyed. The Prophet (peace and blessings of Allah be upon him) said: “There is no obedience to any created being if it involves disobedience towards the Creator.” Narrated by al-Bukhaari, 4340; Muslim, 1840; Ahmad, 1098. Isbaal or letting the lower garment hang below the ankles is a major sin, so you should not obey them if they tell you to do that. But you can wear your clothes at the longest permissible length so that they do not touch the ankles, then you will not be disobeying your Lord by doing that, and you will not be going against your parents’ wishes, because it is not a condition of shortening the lower garment that it should be at mid-calf length, rather you can obey the rule of sharee’ah by not letting your clothes touch your ankles. 
If they insist that your clothes should be longer than ankle length, then speak to them nicely and try to convince them, but do not disobey Allah for their sake by letting your clothes hang below the ankles. 
Shaykh ‘Abd al-‘Azeez Aal al-Shaykh was asked: 
What is the ruling on isbaal (letting the clothes hang below the ankles)? Is it permissible to obey my father when he wants me to let my clothes hang below the ankles? 
He replied: 
Isbaal is haraam, indeed it is one of the major sins. The Prophet (peace and blessings of Allah be upon him) said: “Whoever allows his garment to trail along the ground out of pride, Allah will not look at him on the Day of Resurrection.” And he mentioned the three whom Allah will not look at on the Day of Resurrection or praise them, and theirs will be a painful torment, among whom is the one who allows his garment to hang below his ankles. The one who does this is disobeying Allah and transgressing His sacred limits, so he has to repent to Allah. He will be punished because Allah will not look at him on the Day of Resurrection, and he will be punished because he is given a warning of Hell fire, which indicates that isbaal is one of the major sins, Moreover there is nothing good in isbaal, because it damages the clothes and may make the person stumble, as ‘Umar (may Allah be pleased with him) said to the young man whom he saw allowing his garment to hang below his ankles – who came to visit ‘Umar in his final sickness – “O young man, lift up your lower garment for it will make your garment last longer and is more obedient to your Lord.” 
With regard to obeying your parents, parents are not to be obeyed if that involves disobeying Allah. If they tell you to let your garment hang below your ankles, then you should disobey them, because isbaal is a major sin and there is no obedience to any created being if it involves disobedience towards the Creator. 
Fataawah Majallat al-Da’wah, issue no. 1741 
And Allah knows best.