They can do nothing to AROS.
Well they COULD start yet another "Get legal" -FUDcampaign like they did for MorphOS long ago...
But somehow I believe that it most people wouldn't really care about ANYTHING they say anymore (although at least I wouldn't mind seeing a honest "we've gone bankrupt" statement), and it would damage AROS much less than the earlier campaign damaged MorphOS (their reputation wasn't as bad as it is now)
But then again... Wasn't the original campaign aimed at no-one in general in the beginning? Just "to all parties concerned, get legal or get sued" without naming anyone particular...
Sure they added some fairytale stuff about stolen source code tapes, finding copyrighted code in MorphOS (even if it runs on completely different processor) later on.