Are you going to have sex with him without condom? If not, why is that any of your concern? I'm of course assuming by "sharing things", you don't mean sharing a needle to do drugs together, or you're actually a vampire and will be drinking his blood.
In fact, if he's on treatment, he's likely to be undetectable, which means his HIV would be untransmittable as well. And ever if he's not on that level yet, he'd already have passed the period with the highest viral load, as that'd be the initial months when one could not know one is HIV positive.
Regardless, to answer your first question, yes and no.
Tenofovir could be used for HIV treatment, but it's now also used as a preventive medication called PrEP. With at least four of them every week, one can expect the possibility of an HIV transmission to be lowered by up to 99% (ie better than condoms). And needless to say, one would need to be HIV negative to be on PrEP.
But in any case, he has absolutely no obligation to disclose his health information to you unless he's your sex partner.