Do you think that my former teacher likes me?

Hello, I want to apologize for my bad english because I'm not a native speaker. My story is kind of weird but I guess that some of you may understand it. When I was in secondary school, I fell in love with my headmaster. He was always very nice to me and it seemed to me that he also likes me. He used to flirt with me but it wasn't anything serious. Two years ago I left my secondary school. Now I'm studying high school. I'm not his student anymore but we stay in touch. We sometimes chat on a social site. I see him personally just few times a year but he is always very happy when he sees me and he often asks me when I'm going to graduate. In front of many people, he pretends that he doesn't even know me. I can understand it. It could ruin him due to his job. He supports me everytime I need it. He also told me that he may would like to get a job in my high school because of me, but he is not sure if he is ready to be a high school headmaster. I guess it is not very common to have so friendly relationship with a former principal. I'm in love with him since I was 13. Do you think he may want to date me after I graduate? How can I found it out? I feel like we like each other very much but we don't talk about it. We are something like good friends now.