He's trying to regain his reputation and i think it's a smart move knowing that you might get into jail after running with the money of the investors, but I don't think that would be enough to appease the people he scammed by just returning the money, but i guess it's still a good thing that he returned it, many people would run because of it.
Nobody will trust him again we don't know exactly why he returned the money, maybe he's not really that bad or someone in the group threaten to expose him,we do not know the real picture, this is how risky investing in Cryptocurency so even if you do your own research this things still happen, that is why we should tagged this unknown or anonymous developers because they have a way to get away, because nobody is going after them.