Assalaamu alaykum. What should a wife do if she came to know that her husband earns income through interest? He is earning through halal means as well, including from the property given to her from her parents. He does not spend much on her or the children, and few of them are sick as well. Can they forcibly take his money or completely ignore his money and leave his house?

All perfect praise be to Allaah, The Lord of the worlds. I testify that there is none worthy of worship except Allaah and that Muhammad, sallallaahu ʻalayhi wa sallam, is His slave and Messenger. 

The wife should advise her husband to stop dealing in interest. As for her and her children living off his earnings, there is no harm on them in that even if they are not sick. The husband's wealth is made up of mixed lawful and unlawful earnings, and it is allowable to live of such mixed wealth, as has been explained in fataawa 81560 and 87211.

Shaykh Ibn ʻUthaymeen was asked:

“Our father, may Allaah forgive him, works in a usurious bank. What is the religious ruling on living off his money or consuming food bought by his money? Note that we have another source of income; our elder sister works. Are we obliged to refrain from taking money from our father and have our sister provide for us though we are a big family? Is our sister not obliged to support us and we have to take money from our father? Could you, please, advise us in this regard?” He replied, “You are allowed to take your financial maintenance from your father, and it is lawful to you, and he bears the sin for obtaining wealth from unlawful sources. He has wealth, but you do not, so it is your right that he provides for you...” [Liqaa' Al-Baab Al-Maftooh]

For more benefit, please refer to fatwa 85012.

Allaah knows best.