Can one sibling in a two sibling family change a will after the death of a parent when the original will was 50/50?

I have to agree with the others. The answer is no. I would speak with the lawyer that drew up the will and let them know what your sibling is trying to do.

Jeanne is right. Only the person bequeathing the property can change the will. The executor can interpret it as outlined in the will. For example, he may allow a certain amount of money for expenses accrued in executing the will, but he cannot rewrite any of it.

Now he can write his own will leaving you everything. :-D

Change a will after someone has died? Of course not!