"ooo spooky it's earth and.. uhhhh for some reason that means we need to commit a genocide now" yeah shut the fuck up you evil piece of shit
It'd be fairly suspicious if he DID catch an illness, being from another world and all. The illnesses of this world aren't per se compatible with his body. Especially with it allegedly being an unknown time in the "future". Also, he hasn't spent a lot of times around humans anyway, especially sick ones, it'd be weird if he caught any illnesses from the inhumans.
As for food, it's perfectly normal for different species to be able to eat the same things.
Also, THE INHUMANS ARE STILL THE PEACEFUL SIDE. "the world went mad" fucking bullshit, but whatever, genociding them won't calm the world, and the entirety of human existence is now based on the "madness" like the tech-anisms that violate the natural laws and shit, right?