To answer your question simply: Yes, it’s possible for someone to have regular contact with another person and even to have a physical relationship without love. It’s a poor substitute for the real thing and some people do settle for that. The fact that your friend says there have been more feelings for you suggests that he is capable of developing closer emotional bonds.
Contrary to popular beliefs, it’s not at all unusual for someone not to have yet fallen for someone at 23. He has lots of time. But he will only find someone if he opens himself up to looking. Very few people find true love by sitting around waiting for it to happen. To find love, he has to look for it. That means meeting other available people and being willing to go out with a number of women until he finds the right one. That means opening himself up to being hurt. It also means being willing and able to let other people down gently when he knows that a relationship isn’t going to go anywhere. It means not settling for what is easy but not satisfying.
You can only help him by pointing that out and perhaps being a sympathetic ear and support as he goes through the process. But he’s the one who has to do the looking if he wants to find a life partner.
I wish you both well.