First, mg dealers do not pay 50% of retail. Typically it is 80-90%. If it were 50%, everyone, myself included, would be getting dealer licenses.
The gun has problems, but nothing that can't be fixed by swapping out some parts. The bolt staying back is most likely due to a worn trigger grip assembly or a worn bolt, or both. The grip is a $125 or so 60 second fix. Replacing the bolt is $75-$100 (another 60 seconds). Recommended is to put in an MG3 bolt with internal catch. MG3 bolts fit perfectly with no modification.
Could the problem be from the present operator not knowing how to run the gun? Lots of car owners don't know how to drive correctly, they just know how to get the car to go down the road (more or less). Could be he's trying to load the gun with the bolt forward because he doesn't know any better, or has already bent the pressure plate by slamming the cover down with the bolt in the way. Maybe he ran the old 8 cents a shot junk ammo through it and it's cruddy inside. Could be a weak recoil spring or lack of lubrication. All these fixes are cheap. Virtually the entire gun can be swapped of parts. It's the receiver that's important.
A new feed tray and top cover will likely take care of the feed troubles. Since this gun is a shooter and not a safe queen, no trouble there.... MG3 (.308) parts will fit, and if you still want to shoot 8mm, then those parts are still commonly available for reasonable money $175? for the pair.
A refinish/reblue takes care of the appearance of the gun. Ohio Ordnance would be a prime place to send/take it for a complete going over. Since it's C&R, get a C&R license, and you'll be allowed to cross state lines with it without further paperwork and you could drop it off, spend the day going to the rock and roll hall of fame in Cleveland, and then go pick it up the next day.
Learning how the gun works is easy, but will take a few hours. This is not a glorified Garand or M1A. It's a serious MG which needs understanding to run correctly. Read everything here, and buy a manual or two to see how it all works.
Those are asking prices you quoted. The actual price the seller will accept is likely less. If you can do it for around $25,000, do it. It won't get cheaper, will only go up in price, and if the kids are fed and the bills are paid, toys are what you are working for, right? I went to the bank for the money to get mine.... I've never regretted it for a second.
For the right price, buying a fixer upper is great, especially when it just takes swapping a few available parts and a re-blue to do it.
Darius bought a different gun with serious problems that the seller didn't tell him about. Major headache to get it worked on..... an MG42 isn't that much trouble due to parts being easily exchanged. No tough call here.
And if he decides to sell it for $15,000, and your wife won't let you, let me know right away. I'll be there the next day with the cash, fingerprint forms, and a Form 4 for him to sign. Seriously.