Help me if you can i really need to know?

hi this has been bothering me for years so please help me if you can.my nephew shane died octeber 19 2000 he was 2 and a half years old.shane had tay sachs disease which has a life expectancy of about 3 years old he lasted 2 and a half but then he was always a fighter.when he died he did not talk walk or anything he also got tube fed.as he went down hill he often had problems breathing and had fits.the day he died he was on oxegen to help him breath our family was told it would be hours until hes death and the best thing to do was to give him morphine to make him comfortable so we did and then we took off his mask and he slipped away.myself and my sis held him as he died but as he was dying he kept making a crying noise this has stuck with me since that day and i need to know did he die in pain or was he comfortable.after he died i pretty much broke down i was 17 i then moved to the us as i needed to get away.i think of shane everyday and i need to know