I like a guy at work who is really shy, how do I approach him?

Ok so there’s this guy I work with, he’s amazing! I swear he's like a superhero to me. He’s always doing things for me at work like he’ll put some things away if I don’t know where they go. He comes anytime that I need someone to help with the cash register or the customers. He never complains when I do something wrong or stupid. But there are a few problems with this situation. One is that he’s pretty shy and will basically give me one word responses about personal stuff. Second is that he has Tourettes syndrome. I have no problem with this, but he doesn’t want anyone to know. So a lot of the time he disappears and I feel like he might be off tic-ing and doesn’t want me to go look for and find him. He only has motor tics from what I can tell. Like he does this thing where it almost looks like he’s nodding his head. He doesn’t even know that I’ve realized this. But I’m informed to what Tourette’s is so I was able to recognize what he has. So I always pretend that I don’t see it when he does it. I really want to get to know him. But I don’t want him holding his tics back because I’ve heard how painful that can be.