Autism isn’t the first label I’d be trying to define for your father. It sounds from your description that there are some serious mental health issues (similar to your brother and related conditions) since he seems intentionally abusive etc. toward OTHER people. It is not self-directed.

Autism does not inherently cause this type of behavior!

If you’re looking for a place to start, contacting adult protective services would be an option, along with your brother’s psychiatrist and team to relay your concerns. With HIPAA, they can’t discuss specifics with you, but maybe can give a referral to you for a consult to explain what’s going on at home and figure out a plan. As your father ages, his behavior could escalate to be more physical and harmful. This type of psychological abuse as it is now is NOT ok for you or any of your family members to tolerate. Your mother really needs an ally in you plus additional outside support she can rely on.