Grandfather should not give Zakah to his grandchildren

A man in his 60's living on his savings and supporting his wife and daughter, finds that his sons children go to Canadian public school, where there is no Islamic education. His son cannot afford, out of his salary, to pay the tuition fee of Islamic schools. To send a child to Islamic schools means at least 6 years commitment. It requires continuous income and a lot of money. Grandfather pays some Zakah over his savings; can he send this money to his son's wife and tell her to use it for her children's Islamic education. It has been told locally that one can pay Zakah to his daughter in-law.

Praise be to Allah, the Lord of the Worlds; and may His blessings and peace be upon our Prophet Muhammad and upon all his Family and Companions. Zakat is not to be paid except to the poor and the kinds of people mentioned in the verse. Hence, one is not allowed to pay Zakat to his son's children; whether for their livelihood or education, for they are either supported enough by their father or their father is poor, in which case the grandfather will be responsible for their livelihood. So, he (the grandfather) should not pay Zakat to them since he is sponsoring them and responsible for their expenditure. Hence, the questioner is to know that a grandfather is not allowed, in any case, to pay Zakat for his grandsons' study or livelihood, whether their father is rich or poor or not available for any reason (death or otherwise). He is not allowed to pay Zakat to his son's wife to spend it on herself, for her expenditure is the responsibility of her husband. Allah knows best.