it started smoking so I came back and asked him what it could be, he said right away almost guaranteed it's head gasket and truck is probably not worth fixing
going to be proper I said ok.
I can pay the $13k bill now or $15k put back together
You own a truck that blew a head gasket. There's no "can you get me 500 miles" fix to that situation. Its going to take some money.
You took it to the guy next door, and he flat out told you "its probably not worth fixing". I'm not entirely sure what all happened right after that- maybe you thought he'd put his x-ray vision glasses on and his fortune teller hat and come up with a $3-4,000 miracle cheapy repair, or give you a total itemized list of everything he's going to find once he gets inside. Either way- you didn't drag it home right then- you left it at his yard. That to me means "I want it fixed".
You're at 13k for a pile of parts, and at 15k put back together? or $25k put back together? I'm not sure and I really don't care. At the high figure that's only $18,000 US for a engine head repair and removal/ reinstallation of rear suspension and frame rail repair. Sounds a little high, but I think the last head/ and gasket replacement I had done at shop was close to $10k and that was before "covid inflation" prices. Maybe a "this is a POS truck" cost for the "I hope he's not my customer anymore" price rate.
You took him the truck, he said "its probably not worth fixing" but you knew better- and you gave a verbal go ahead. He's a mechanic, not a auction house or a buyer and fix it and resell it house. Its your truck that you wanted fixed. If you didn't want it fixed, don't take it to the mechanic. I don't expect a repair shop to make business decisions for me.
Paper work orders only matter to paper pushers and lawyers. If I say "go ahead" then I mean "go ahead" and I'm paying my end, because I said I would, not because of some papers.
And as far as "warranty"- nobody is warrantying a 35 year old band aid engine repair- there's a whole pile of other bad things that can happen to a engine that age- because he's not replacing everything- just fixing what's wrong. Full warranty doesn't happen on a band aid repair- if the head gasket price is giving you the vapors, a full crank out/ injection pump/ turbo/ liners/ mains/ pistons/ head price would send you around the bend.
If you don't like your neighbor mechanic, well then don't take him your truck anymore, find another shop. The rest of this is 10 pages of you crying about the cost to fix your old truck. You don't work for free, I don't know what makes you think your neighbor mechanic should.
You want to have a dump truck- fine- you either pay for it in new purchase price, or in repair prices- none of my equipment runs for free. Anyone running a 30 year old truck better be able to fix it themselves, or be ready to pay for a $15,000 repair at any time. If you can't do either of those, maybe you shouldn't own a dump truck.