Alexander was certainly worried about the backwardness of this time's medical technology.
Especially because he knew he had no easy way of advancing it anytime soon.
He estimated that the medical technology even a few decades from now would still be comparable to now, and the reason for this would be because he was no doctor.
He only had A level biology knowledge, and whatever he taught up until now was around the limit of medical expertise, while the truly effective medicines, like penicillin, were way beyond his capabilities.
Alexander did read that Flemming had discovered the magical cure accidentally when he left a petri dish to grow mold on, but that was the extent of it.
And even if he could somehow replicate that and produce that exact mold, there was no way he would be able to refine the mold into anything remote close enough for human consumption following that discovery.