Can I retain a home aide for him?

From what I have read, hoarding is considered a form of mental illness. Also, if he's aggressive, it could indicate that some more than age related decline is involved. If he's not mentally competent, he may need real intervention by professionals to assist him, regardless of whether is is aware of it. Adult Protective Services may be able to help or you could talk with his doctor, if you have that authority.

Just a note; hoarding and aggressive behavior are not "age related decline". They are indicators of mental illness and/or organic brain disease.

Does he have a doctor? While his doctor most likely cannot talk to you about his symptoms, you can report them to his doctor.

The office is on Union street. 615-862-8828 They have a website.

I live in Nashville TN. I have not heard of this resource.

Would he allow someone into his home to care for?

Would you consider calling your local Area Agency on Aging and asking for a needs assessment? If his living conditions are truly unsafe, they can take action.