You do not say whether your mother-in-law had an estate plan that gives your sisters-in-law the right to to sell the house. Find out if your mother-in-law had an estate plan (will, trust, beneficiary deed, etc.). If she did, find out the details of the plan. If your mother-in-law died without a will or other form of estate plan, then her children share equally in the assets. However, since you are not a blood relative, in Missouri your son gets his deceased father's share.
Answered on May 20th, 2013 at 12:12 PM