I never played Raid in Facebook, do I have to do something before January so I don't lose my account. I always played through Plarium.

@OP - you're going to need better champs than a low-grade epic who happens to have destroy. The boss hits quite hard, and is very disruptive. My expectation is that he has no room on any team, at least not on hard.

But to answer your specific question, yes, destroy generally is capped at 60% of their max hp.

No you don't.