Legal Question in Wills and Trusts in Massachusetts

Yes, a person can amend or revoke their Will at any time as long as they are mentally competent.

Only the person who wrote the will can change it. Family members have no rights to change other people's wills.

I agree with the previous answers. You always have the right to change your own will, so long as you have capacity to do so. But you may not change the will of another person unless you have been granted that power by a DPOA or some other grant of authority. If you are going to be engaging in estate planning or medicaid planning with an elder, I strongly advise you to meet with an attorney.