I forgot this yaoi, it had a lot of sequels.
This middle aged guy has a fever and stuff so this student takes him back to his place and takes care of him, after he gets better he says he'll return the favor and then he hears the neighbors about to do it then the middle aged guys gets an idea and jacks the guy off.
Turns out the student is actually a waiter at a cafe or restaurant the guy frequents... what else... they eventually end up living together for reasons.

NVM, FOUND IT

Can you please tell me what it is called as I would like to read it!

Sersa, I think it is Otokogokoro and its sequels.

Thanks dalek