Hon, I'm so sorry that happened. Question though, did he ever do that before the last group of fosters came? Could it be stress from that? If you're like me, you couldn't care less what the reason is, he better not do it again! Mel might have a good idea, he made need meds to help him get over the stress.
Seems we're all having melt downs from various things. Hang in there girl, we're thinking of you.