Any one of the three facts you have mentioned could be enough to derail a good, new relationship. If it quacks like a duck, stars in a series of Aflac commercials, has webbed feet and falls under the taxonomic family Anseriformes, yes, it's a duck.
The impact of serious on going health issues, particularly if they're acutely presenting again, can be fully consuming and too hard to balance with other (desirable) things. Couple all that with heading a business and pouring 80+ hours a week into it - you have a Webster's definition of overload.
My advice is to not look for other self-sabotaging reasons why the relationship isn't full steam ahead, but rather appreciate where this dude finds himself and see how you can find a dynamic that might meet your needs and his. Probably, this can only be derived from a few hard conversations on the matter. It won't be easy. He won't want to lose you and you probably don't want to be the "selfish bad guy." But with some honesty and bigger picture mentality, hopefully you guys can create a platform that works. Also keep in mind, his situation is fluctuating. With any luck his life load can lessen. The things he would like to pursue may quickly take priority again...
I'm not saying just shut up and wait in the wings, but I am saying a duck is a duck. Act accordingly.
It took me a while to learn this lesson....when a guy tells you he doesn't want a relationship believe him. The reason doesn't matter. He says he doesn't want one he doesn't want one. Guys do go after what they want. Wouldn't you want to be wanted?
He might be using anyone of those issues as an "excuse" to be able to tell you doesn't want to have a relationship, but no matter what the bottom line is that he doesn't want a relationship - the motives and excuses don't really matter.
Seriously. If a man wants a relationship with you, he pursues it. If he says any of those "excuses", its merely the same thing women do when they say they are "too busy" or "its not you, its me"; an attempt to soften the blow.
I know a guy who had started his own business, he put in 12+ hours every day, was so tight for cash he slept in his small office space and used the gym facilities for hygeine. That sure as hell didn't stop him from going for his now wife.
A brain aneurysm alone, ruptured or not, can be such a huge event that recovering from that alone can take so much time (years),and focus. Add cancer to that and you could have a guy that might only be able to concentrate on his wellness right now. Plus 80 hrs/week with his own business and wow..hes' quite a guy.
He didn't raise the white flag of defeat and self pity, rather he continues to move forward. He might need all his focus just to stay the course and have nothing left to offer you.
This is a similar situation that I am in after dating a guy for 2 months and has similar stressful work/health issues and decided he couldn't commit to a relationship right now, but the guy says he wants tot be friends and stay in touch. I know there is a chance that i'm just being told what i want to hear, but if his situation is really that stressful is there any hope that maybe when things slow down that he might still show some interest of wanting to pursue a relationship again if the lines of communication stay open?