Giving zakaah to one’s mother if her husband does not spend on her

It is not permissible to
give one’s mother zakaah that is the share of the poor and needy, because
spending on her is obligatory upon her husband; if he is poor or refuses to
spend on her, then her children must spend on her. 

Ibn Qudaamah (may Allah
have mercy on him) said in al-Mughni (2/279): If the poor woman has a
husband who is well off, he should spend on her and it is not permissible to
give zakaah to her, because she will have what is sufficient for her by
means of what reaches her of that obligatory maintenance. If he does not
spend on her and is unable to do so, it is permissible to give (zakaah) to
her. This was stated by Ahmad.

End quote. For more
information please see the answer to question no.
102755 

If she does not have proper
maintenance because her husband is poor or miserly, then her children are
obliged to spend on her enough to suffice her, if they are able to do so. 

Ibn Qudaamah (may Allah
have mercy on him) said in al-Mughni, 2/269: Nothing of the
obligatory charity (zakaah) should be given to one’s parents or children.
Ibn al-Mundhir said: The scholars are unanimously agreed that it is not
permissible to give zakaah to one’s parents when the one who is responsible
for their maintenance is obliged to spend on them, and giving zakaah to them
will mean that they no longer need this maintenance, in which case
maintenance would be waived in such as way that he will benefit from that,
and it is as if he gave the zakaah to himself.

End quote. 

But if they are not able to
spend on her, then it is permissible to give zakaah to her, because it is
not obligatory for them to spend on her in that case. 

Shaykh al-Islam Ibn
Taymiyyah (may Allah have mercy on him) said: It is permissible to give
zakaah to one’s parents and grandparents, no matter how far the line of
ascent reaches, and to one’s children and grandchildren, no matter how far
the line of descent reaches, if they are poor and he is unable to spend on
their maintenance.

End quote from Majmoo‘
al-Fataawa, 5/373. See also: ash-Sharh al-Mumti‘, 6/92; and the
answer to question no. 85088 

It is also permissible to
give zakaah to the mother under a category other than that of the poor and
needy, such as debtors, because it is not obligatory for him to pay off his
mother’s debt, so it is permissible to give her zakaah in order to pay off
her debts with it; rather she is more entitled to that. For more details
please see the answer to question no.
39175. 

And Allah knows best.