My best friend is gay, but we keep getting closer, IS anything possible?

My friend and I have been steadily becoming close since the beginning of this past summer, things went from disliking eachother to nearly insepparable in a very short amount of time, now we spend every second we can together, text all day, and we get anxious if we have to spend more than a day and a half apart, we spend hours upon hours just talking, we almost get kicked out of restaurants because we stay there too long, we never run out of conversation! we tell eachother "I love you" and he recently "proposed" to me as what I thought at the time to be a joke, but he was embarred the next day. All of our mutual friends think something is going on, even people who don't know us well at all are convinced we're more than friends. His parents, among others, think we smoke pot or something together cause we're just too happy together.He's recently gotten more physical, more hugs, more "pretend" kisses...we can look into each other's eyes and say what the other's thinking...the works...I DO love him dearly, I just don't know if it's ever going to develop into something bigger, sorry this is so long, but what do you think? Impossible? or does the impossible happen?