Under the Hindu Adoptions and Maintenance Act, 1956, a widowed daughter-in-law is entitled to…

The proviso to section 19(1) makes the father-in-law liable only where she "is unable to maintain herself out of her own earnings or other property" and cannot obtain maintenance "from the estate of her husband or her father or mother" or "from her son or daughter, if any, or his or her estate". Each of these sources must fail before the father-in-law is liable.