I'd sell the Silverado to pay for Tahoe transportation and parts. The Tahoe has sentimental value, the Silverado does not. If the FIL doesn't agree to that, then he can take his truck back and you'll simply be back where you were.
My FIL is a COMPLETE ******* and he will not agree to that. He told my son when he gave it to him that one of the conditions of accepting it was that he could not sell it, and my son agreed to that. But I have not spoken a word to him in the last month ever since me and him got into it. He flat out called me "lazy" because I have a bad back. I had a major back surgery barely two years ago, and he expects me to just be able to bounce back from it like nothing happened. Not only am I still in a lot of pain, but now I can't bend my back as far. Just putting my damn socks and shoes on is a painfully strenuous ordeal, and I usually have to ask my wife for help after I do one foot.
He is one of those old farts who thinks he knows EVERYTHING and the second you disagree with anything he says or does, or show him the correct way to do something, or even just prove he is wrong about something, he starts getting mad and all pissy with you.
He bragged about how he took suck good care of that 99, and he told my son that he better take good care of it too. He handed him a folder with all the "maintenance" he had done on it, but I dug through it and it's nothing more than Walmart oil change receipts, Quick lube oil change receipts, New tire receipts, and a few actual repair invoices for brakes, belts, an AC compressor replacement (which has already failed again I should add).
I helped my son change the oil a week after he got the truck, and there was a damn universal rubber oil pan plug on there because the oil pan is stripped out. That's what happens when the dumbass at the quickie lube uses an impact to tighten an oil plug on an aluminum oil pan. Then it has oil leaks from just about every gasket. The power steering fluid was basically gushing out (I repaired that already) and the suspension is COMPLETELY shot. Every bushing and all the ball joints and tie rods are beyond worn out. And EVERY body panel has body damage on it.