A way around the problem of challenges to a Will is to include a no-contest clause, according to Press Enterprise in "The Pros and cons of the no-contest clause."
A no-contest clause helps prevent these challenges. It simply states that anyone who challenges the Will will forfeit their right to receive anything.
As a result, the document will be effectively rewritten to disinherit the challenger.
This is an easy way to stop many people from challenging an estate plan. They might not be happy with what they received, but they do not want to risk getting nothing.
Some criticize these clauses as deterring people from challenging an estate plan when they have good reason to, such as when there has been undue influence used by someone else to get more of the estate than he or she should. However, most states will not enforce a no-contest clause if the person challenging the Will has cause to do so.
An experienced estate planning attorney can advise you on creating an estate plan that fits your unique circumstances and could include a no-contest clause.
Reference: Press Enterprise (Aug. 5, 2017) "The Pros and cons of the no-contest clause."