I gave my number to a guy I'm not sure is gay, he texted me. How should I proceed?

A little backstory:There's a guy in my class who I really like. The first conversation we ever had was because I asked him if I could try his glasses on because I really liked them. I said they looked better on him to which he responded that I looked good in them. We talked a lot about ourselves for a while and felt a little chemistry between us. At one point I told him he looked younger for his age and he smiled, got a little shy and said thank you.Now he always tries to sit next to me in class and whenever someone tells a joke or something, he always looks at me first to see my reaction. He also likes to touch me out of nowhere, such as pat on the back or hand on the shoulder.One day I told him "you look handsome today" and said thank you after a few seconds of silence, like he was trying to process what I just told him. I decided to give him by number asking if he wanted to get a beer that night, but he had to work. He said "I'd love to, man". (It's silly, but I'm worried about him referring to me as 'man'). He texted me two days later saying he's sorry for not texting sooner but he's working a lot and we'll keep in touch as he finds some free time since he's very busy.Now, it's a good sign he texted me, but I'm not sure if he's just being overly friendly and wants a friend or he's actually interested in me romantically/sexually. Should I treat this as a date? What I'm not sure how to proceed is, should I tell him I'm gay directly or just start being friends with him and slowly come out to him by my actions. If he's still in the closet, I don't want to scare him off.