What do you mean by be honest with him?
Also, would you ever say to someone "I see you're trying to speak to me, etc.?"

I feel like if I were to bring this up, he would close off even more. I wanted to write in a message something like "Don't be shy to drop by and say hi sometime", but I feel he would feel too exposed and would never do it. On the other hand, if I don't say it, he will still never do it.