does the widow have a leagal right to dispute the will or any recourse to claim more than what she was left with ?

A husband dies.The children from former marriage produce a Will signed on his deathbed prompted by them the night befor he died of bone cancer.children take all monies of husbands,even the funeral donations.Widow is harassed into giving up all memorabilia of her husband and eventually pushed out of the house which she is 2/3 owner. Kids now rent the house out and have no contact with the widow.