I just thought about him saying “where to find his will.” You aren’t next of kin. You’ll have no access to his place or his belongings. Even if you had access, you can’t go rummage in ex’s belongings after their death. His brother will be in charge of it. Not you. In fact if something happens and you start talking about knowing where is his will, they won’t appreciate it. Even when people leave something to friends or not immediately family, they don’t give them instruction on where the will is at. You have no authority on what happens in case of ex’s death

Id tell your husband (or ex husband) to stop this nonsense.