Well, you've got the TIPM, which makes any kind of diagnostics tougher than the old-timey fuse system. My suggestion is to electrically isolate what this guy put in the truck and see if everything returns to normal. Then start reconnecting one-by-one until you find the problem. If you are not electrically knowledgeable, your only choice is to take it to a dealer.
The TIPM seems to work pretty well when it works, but is rather sensitive to shorts and unusually large currents. When it sees these, it tends to give up.
As a side-story, here's what I think happened. This guy hacks your electrical system unaware of the subtleties of the TIPM system, breaks it, and then weasels out of fixing the problem. God forgive me if I'm wrong, but I don't buy the "my dad is in the hospital" bit. Maybe I'm too cynical, but I've heard too many excuses from "shop owners" in my day - including "my [insert loved one or pet here] is [insert ailment]. " Seems like every time a job goes wrong...
Back before the weight of the world crushed my spirit I believed the excuses. Sigh.
-Ryan