This is really very interesting. He stole one of the largest amounts and again returned half of it!!
There's still long way until
all the funds are recovered. Let's not be calling the hacker "nice" too early

the hacker allegedly fucked up and made an extremely rookie mistake by sending a certain amount of the stolen funds on a centralized wallet. Hence apparently why this hacker has suddenly had a change of heart and is now trying to be a white hat lol.
If he wanted to be a white hat he could have asked for a reward for telling the flaw. Now he's more like fighting to not lose his freedom.