They've returned it all except for $30m Tether which was frozen by the developer. The "hacker" is being offered $500k "White Hat" bounty but hasn't accepted it yet. Weird. If you thought you were going to jack $600m in crypto you would probably spend a great deal of time and energy on a plan to convert it. It doesn't make sense.
Yes they have recouped $610 million and the remaining $33 million usd was released by tether. At least that’s what the reports say.