Is it incumbent on a family to provide for its old handicapped son and take care of him?
The family and relatives - e.g. brothers - of such a person are obliged to spend on him and take care of him if he didn`t have money of his own.
If the imam does not leave time for reciting Surah Al-Fatihah, is the recitation of Al-Fatihah waived for the follower?
The recitation of Al-Fatihah is not waived for the follower. They should recite it silently, even if it causes a slight delay in following the imam in bowing (Ruku'). And Allah Knows Best.
Is it permissible for a man to marry up to four wives (polygamy in Islam) for pleasure although he can`t afford that?
It is desirable for the man to have one wife if there was no need for him to have more, if he can't afford marriage forthcoming expenses.
A man donated a burial plot, but before registering it in favor of the Ministry of Awqaf and before burying anybody there he said that he didn`t want to donate it and planted it. What is the ruling of Sharia on this?
All perfect praise be to Allah the Lord of the Worlds. May His peace and blessings be upon our Prophet Mohammad and upon all his family and companions.
If he had endowed it as a cemetery, then he can`t take it back, even if he didn`t register it in favor of the Ministry of Awqaf. If he said: "I have endowed this plot as a cemetery, then it becomes an endowment." However, if he didn`t endow that plot-but it was his intention to do so-then he is allowed to back down. And Allah The Almighty Knows Best.