@'Demi - Nah, I love arguing about these things
To answer.
1. He's not immune to drugs, just resistant. Also, this doesn't come from the skull suit, its just something he got from taking drugs at a young age.
2. The skull suit doesn't make him stronger, jt just removes the limit. The human body can use only 30% of its built in strength or it would hurt itself. This means that the limiters are released, but his entire body experiences the pain. If he goes too far, his organs will shut down and kill him.
Before you argue about realism, look at your story and the 1000 swords you're using.