I think that it can work, but may not be the best idea if your friend has previously expressed feelings for you. He may be saying that he can handle it when, in reality, he's just trying to get closer to you. If you think this is not the case and you periodically reevaluate how it's going, I think it can work. I had a similar situation (no health issues, we both just were not ready to get back into committed long-term relationships and were lonely) that worked out fine. That being said, I've had much better sex when in love. I've also had a GREAT time with one FWB relationship that did not involve sex....we watched movies and cooked together and even fell asleep in the same bed, but neither one of us was attracted to each other, so there was never any sex. Sometimes a "cuddle buddy" is really what's needed. The companionship, respect and the physical contact were all the benefits that were needed.