Hey, Pinkerbell. I happen to be a guy who would act like your friend. I'm INFJ, I struggle with loneliness, finding genuine people, and someone understanding. When I meet a girl who I can have real and deep meaningful communication with there is nothing like it. It's refreshing and calming, helps sort out a brain on the brink of crazy. But in those instances girls become close friends and loyalty and love kicks in. It's like I want them to stay just as my best friend because they help me more than they know but still get jealous when they talk to other guys (usually only jealous when I don't like the other guy, maybe it comes from fear of loosing the friendship, time, and closeness to another person). Our personal loyalty will also drive us to be the perfect gentleman for the very few friends us INFJ's actually have. Like, it is take a bullet for you literal loyalty. A lot of times it's taken as flirting but it's actually the way we show our closest friends that we value them. We value them so we take care of them. Love (or I should specify attraction) eventually comes along and things get flirty and playful at times but like I said before, no actual intent of going further, it's simply giving into the natural feelings that start to occur in the situation. It's what happens when two people get close and spend time together.
So I believe this guy is depending on you as someone he trusts enough to let you into his chaotic mind and help settle/calm it. It sounds like he values you a ton as his best friend, being a gentleman is just his way of expressing to you that you are appreciated. And ask him right out if he wants to stay in the position as friends you currently are. Keep flirting on low or love chemicals start to fly and then the hearts get hurt. I don't think he would leave you, he depends on you too much as a friend to easy his mind/lonliness.