Is there a time frame on contesting a will

Person in nursing home and will written with person having medical issues ( slurred speech , abnormal labs, had periods of confusion) person writing the will children benefits from it. Person passed away and person writing will is executor of the will. She gives next of kin part of will at prior to funeral. Person present next of kin and with addendum to will approximate 7 mos 3 weeks after property was probated giving her children half of property