In meet the team it literally keeps heavy alive while HIS HEART AND LUNGS ARE MISSING

hmm

ther is a literal comic about this

I know, read the rest of the comment section

It can

its because it heals the team based off of a template, and demoman's template is missing an eye

Oh ok

I hate to be that guy, but according to the lore, he tried multiple times but failed

I know, everyone else already mentioned that

Clearly you never read the comics medic claims he returned demos eye multiple times but on Halloween it comes out of his head as an eye monster

Oh ok

I'm not a massive fan of the series, I haven't really read the comics

we may never know

Well, every Halloween, it comes out as an eye monster. Hence forth the eyepatch to keep it from coming out.

I know. His eye socket was cursed by the bombonomicron when he was a young lad and now every time medic brings it back, it turns into an eye monster. I'm enlightened on tf2 lore now