Hi Talauria, it sounds like you're a very caring person. Kudos!!!!!
But it might need to be about putting yourself first for a change as you're so conflicted about the relationship. I get the feeling you're more in the habit of caring/thinking about others than yourself .
If he is "unintelligent" then yes maybe he can't help certain things, maybe the chances of him changing some of his behaviours is quite limited..............but that doesn't need to mean that you have a duty to put yourself in the relationship to the extent that it's damaging to/hurting you. If you need more distance from him (physically or/and emotionally) then that really isn't unreasonable at all, and no-one (not even you!!!) should judge you badly for that, in fact it might even help the relationship if you want one.
And you know if he does say something hurtful to you, then you're already streets ahead on that one..........you know that it's not "personal"/intended to be hurtful/has the same meaning as "someone else" might give it if they were to say that, so maybe you could try to let some of that hurt go?? Of course, tell him if something he says/does is offensive, but in yourself you know his understanding is limited when he's saying/doing those things.
And when he's slipping into some of his "stereo-types" let him know if those views are offensive (racism- very offensive!!)...........just wondering if people have been letting him "ramble" on with them/letting him think it's OK, because "that's just him"/"he can't help it"/"he doesn't know any better" at the time/s.........not you, but people............
Non-offensive controversial opinions.............well that's kind of like weighing up whether you can accept differences in those specific opinions or not..........agreeing to disagree.........
So about setting some boundaries, hey??? How much you want to have to do with him, what you'll accept from him, where you're going to insist............
And while you're feeling sad for him..............I know his difficulties are really standing out for you.........age, loneliness, health............because you're so caring, is that the complete picture?? Are there things not to feel sad for him about, things that aren't going so bad for him?? Perhaps there are more "better" things going for him, that are slipping into the background.........and perhaps when he's talking to you it's a lot more of the difficult parts he's bringing up.
And if you feel you want/need a relationship with him, then maybe have a think about how that might work..........e.g. any simple/casual/enjoyable activities you can do together where a bit more of "the best of him" might show, any levels you can "meet on"..........??? Remember it's you calling the shots on what might work a bit better now, it's not you trying to fit in with the situation as it is. You'll probably have to make some allowances but.............
Still it is entirely up to you, please don't feel guilty if you need to walk away. Sometimes you (anyone!!!) can only do/give so much, you'll have clearly tried, and (again!!) you need to put/care for yourself first at times. He is not your responsibility...........
And if you want to talk more..............

Alison