Is he gay?

This is kinda long.

I like someone and I do not intend to come out to him. I can't risk our friendship.

However, he is sweet and he keeps and open communication with me (although most of the time it is me who initiates). Sometimes, we do not have communication for 3-5 days, but the exchange of messages resumes. He is like a tamer version of Mr. Krabs in Spongebob Squarepants, yet he sends almost constant SMS messages to me.

There are times when I feel that he knows my feelings already, because he is sometimes uncomfortable to be seen by my colleagues with me. He is kind of a loner most of the time. Sometimes, I can feel that he is avoiding me in the flesh, yet after a few hours we will have conversation through SMS and social media.

He flatters me with things (like I look good, that I look like a heartthrob). He throws jokes, makes me laugh, and support me whenever I feel down.

Sometimes, I can feel that he likes me, too. But that feeling is inconsistent because sometimes I feel he does not want to hang out with me (maybe he only likes to talk through SMS or the social media).

Some of my friends say he is gay, but it is never confirmed, for he acts straight and interested with straight guy stuff. I heard he tried to court a girl before, but he never had a girlfriend (and he is approaching 30s). He said he likes a girl, but never made a move to pursue her even though they are both available (the girl heard this and did not believe that he truly likes her).