Need help, Just bought jeep with major rust issues.

I am in Montreal Quebec and am in a bit of a pickle with this jeep I just stupidly bought. My mechanic lives a good 35 minutes from my location so I gave a half decent once over of the truck before barganing. The guy said good to go no issues yada yada. The second I took it to my mechanic he said take it back because the guy had a plywood board over the passenger side floor because its soft from the rust underneath. My mechanic made it sound like my truck would snap in half if i hit a bump wrong but it sounds to me a bit extreme. He is a buddy of mine as well and i know he can be dramatic haha. It is a 1996 Jeep cherokee sport with the 4.0L. Engine and mechanics feel quite nice and i dont notice any crazy noises or anything. Fluids all AOK. But he said the floors of the front and rear both sides are rusted to hell. I dont notice an issue when stomping on the floor on drivers side but what do I know... Can I get my money back from this private sale or should I keep it till I can dump 2000 into the floors? I love the truck i just dont want to have a nasty safety hazard on wheels.