He will bleed if cut, but doesn't actually need blood, so he can't bleed to death
The only way to 'kill' him is to completely destroy his body, for example by burning it
The stone will keep all of his memories even if his body was destroyed, so if he was made a different body and the stone was inserted into it, he would remember everything from his 'previous life'
Doesn't feel pain
If the stone inside him was removed, he would start looking for it, slowly starting to become more and more enraged, and kill who ever would try to get in his way
After getting the stone back he'd quickly turn back to normal
He has trouble understanding humans/human emotions at times