My dad and his mother were joint on a checking account since 1986. She told him in May to go ahead and write a check to make her funeral arrangements, pay her personal bills, etc. She was in the hospital. Since his name was on the account, he signed the checks for her along with his name. His sister has stepped in as a Power of Attorney August 1st. She says she was entitled to all the money in the account. My grandmother had already given it to my dad months prior. She is now stating that the checks have been forged and has gone to a criminal defense lawyer. Is my dad protected?