Stick with your restoration plan in honor of the father as you originally posted.

You bought the games for their selling price (worth to the seller) back THEN. Should you even consider setting a price and offering them back to the sons (and I think you definitely should NOT because they're your games now and you already said that you don't want to sell them), that price has to minimally be what you consider them to be worth to you NOW.

This is incredibly analogous to the proper attitude to adopt when gambling in a casino: be it known that you are *NEVER* playing with the house's money. Whether it's the stack of chips in front of you on the table or the credits on a machine, those represent YOUR money. And that's precisely where the notion of "the house's money" came from: chips and credits are intentionally designed to emotionally manipulate you into devaluing your own money. So if you hit a $1,000 jackpot on the very first thing you touch and then spend the next three hours giving it all back, you didn't "have a good time" and "had fun playing with the house's money." Nope. Quite the opposite: you lost $1,000 of your own money because you could have taken your winnings and left. But you didn't (like most people, myself included all too often) because devaluing money via chips/credits is one of the hundreds of ways casinos are constantly manipulating us emotionally from the moment we pull into the parking lot. (And if you don't believe chips/credits make you instantly devalue your own money, imagine if instead of using using chips/credits, you had to reach in your pocket and put the same amount in actual cash on the table or into the machine every time you placed a bet. The casinos know that people would likely not play as long if they had to play with cash only - so they generally don't let you.)

The sons are trying to manipulate you emotionally. Don't let them "guilt" you into parting with YOUR games. Do yourself a big favor and re-read your original post - as if someone else was asking you for advice in the same situation. There. You are officially absolved of the sons' attempted emotional manipulation. Restore those games in honor of the father and never look back.