Not everyone "needs" to have a boyfriend/ girlfriend to "complete" them. Some people are not going to be "lonely" or "alone" if they don't meet someone as they go along in life.
Someone can be alone and be very happy. Its just a different happy to what you expect them to be or think they should be. You can't shoehorn everyone into the same box.
Maybe he just doesn't want to find or have a partner yet because he just hasn't clicked with someone.
Maybe all the girls/ boys he meets are complete selfish shallow arseholes who only care about themselves and he can't be arsed to deal with their crap longterm! If so, you go boy!!!
My mum told me I never had to have a boyfriend, get engaged, married or have kids unless "I" wanted to. She didn't want me ending up trapped in a shitty relationship JUST because I thought I had to grow up to follow what other people expected me to do.
I was around 26 when I got my 1st real "boyfriend" and I'm still with him 22 years later.
I just wasn't interested in sharing my happy and valuable time with a "significant other" or just go out with someone long term for the sake of "having a boyfriend" because that is what people thought I was meant to do.
Got asked out a lot but frankly I felt nowt for the person doing the asking. I was merrily going through life with lots of pals and a very healthy social life and then got unexpectedly smacked in the face by the lurve bug (I actually walked face first into the poor man!).
Also having a girlfriend/ boyfriend doesn't instantly solve someones problems or take away their loneliness. It can even make things worse if they end up with the wrong person just to make their parents or friends happy by having said "girlfriend/ boyfriend" so it shuts them all up.
Would you rather he waits until he finds someone he can connect with on all levels and be happy being with or do you just want him to have any old person to call his "girlfriend/ boyfriend" so you can stop worrying that he isn't "normal"?
If it's the former, stop worrying! He will met someone when he meets them! Be happy when he is happy and be there when he is feeling low.
If it's the latter then..well... meh to you.