Sounds like a "Life Crisis" to me. My father retired early and had the run of the house for ten years. When my mom was set to retire, my dad started freaking out - really self-destructive behavior. My mom was a control freak and had already created a "To-Do" list that was a mile long. My dad took it as his 10 year vacation being over. Through some intense compromise, my mom learned to relax and take those projects one at a time. My dad learned that he was going to have to contribute more than playing Mah Jong on the computer all day.
You could encourage your father to pick up a new hobby. Surely there is something he has always wanted to do, but never had the time. This will "show" him there is life after this change. My father took up guitar and bird watching. My mom retired and immediately joined the Red Hat Ladies and started her own business making "Father Christmas"es.
Over time, your father will come to realize that this change in life isn't so bad. He is probably really conservative (read: resistant to change) and just needs time to figure out that life is really just beginning.
Also, I would imagine that your father might have a hearing problem. Some of the things you are listing are key indicators. I would get his hearing tested. People become really defensive when they have trouble hearing/seeing.
You and your mother getting prescriptions for Zoloft won't hurt either.
