can you eat a lobster that was frozen alive?!
They is the best way. Just drop them into a pot of boiling water and cook them until they are a nice pink/red colour, about 20 minutes depending upon the size.
Did he buy them at a grocery store? Are you sure there not cooked? I have never heard of frozen lobster not cooked but they freeze shrimp with the head on raw. I would call a grocery store or a seafood market.
I don't think it would be safe. It depends on how long it has been since they were caught and frozen. The cooking would have killed bacteria.