As the agent for your mother pursuant to her Durable Power of Attorney, you are in a position to exercise control over the real estate on her behalf. I am
assuming that your mother owns the home and therefore you are authorized to act on her behalf in regard to this home. You indicated that your brother is not "actually a tenant." Although there may not be a lease, he still may be considered a tenant under an oral tenancy. If he is not a tenant under either an oral agreement or a written lease, he is only a guest and does not have any continuing rights in the home. He certainly does not have the right to change the locks. I suggest that you contact your brother and inform him that as your mother's agent under her Durable Power of Attorney, you are asking him to give her financial information that he has to you and also to vacate the premises for your mother's benefit. You can let him know that if he refuses to do so you will file a criminal violation for trespass. Ultimately, if he continues not to be cooperative you may need to hire a lawyer, but the threat of a criminal complaint may be sufficient to get him to leave.