Vader redemption and how would you punish him?

There are those that say Vader dying to save Luke isn’t enough for him to be properly redeemed, I say it’s not his fault he died before he could do more. Let’s say he lives and post Endor you decide his fate and how he is to pay for his misdeeds what do you do? One rule you can’t execute him because than he might as well have just died on the dearth star.