Sold On A V6, Turns Out It's A 4-cylinder- What Can Be Done?

Location: Texas

Hey everyone, gonna try to keep this short and I'm not sure how relevant certain details are. I was not there with him. This was the first time he made a purchase of this magnitude for a vehicle.

Today, my fiance bought a 2022 Toyota Tacoma at a dealership for about 29k (originally 31k) with 8.89% APR I think, and he was under the impression it was a V6 engine in it. The dealership kept telling him it was a V6, and was basically selling him on the idea that it was a V6 during the test drive. His brother was there with him the entire time and witnessed everything they talked about. There is nothing on the paperwork indicating in words anything about what kind of engine is in it.

He gets a loan through a bank, and it's seemingly all good. He got it on his insurance tonight too.

Turns out, it's actually a 4-cylinder and the VIN on the paperwork confirms he was sold a 4-cylinder, even though he was told time and time again-- even double checking with them at the end that it was a V-6. If he knew it was a 4-cylinder, he wouldn't have gone for it or at the very least he wouldn't have spent so much. He feels cheated, and is really beating himself up over it all.

My question is, what can actually be done in this situation? They misrepresented the sale, right? He's going to call them as soon as they open tomorrow, but I'm concerned about him getting screwed by the bank or any confusion happening with the insurance.

How simple is it to just keep the truck and "fix" the contract and the loan to be for a more appropriate price, considering it wasn't financed in house and it's been less than 24 hours since the sale? Does this need to be escalated if they don't agree to this? Does he even have grounds to fight them on this?