That's terrible that someone ruined your rifle. I am an old timer lefty and been looking for Mark V in .257 used for years that is a hunting rifle, not collector. As I read the story, I was hoping that the rifle might be for sale. But if a new barrel and bolt or even possible gunsmith work done on the bolt to make it a usable rifle again. At any cost over a few hundred for just the rifle. After repaired, the owner would be upside down in money spend vs worth.
As a side note: I found a 1980s LH 7mm mark V, 3 years ago at Cabalas for 1500 that had been rebarreled and had same vintage Leupold scope. It was there for around 6 moths that I knew, I offered 1000 and got it. It shot great, bluing was in bad shape. I ungraded the scope, after some shooting at the range the stock split. I replaced the stock with a custom composite and had it reblued. I now have 2400 invested in a rifle worth? Maybe 1,000-1500. It does shoot great. But is a money pit.
It makes me sick to hear how that .257 was ruined.