Texting a guy on his birthday?

For roughly 5 months last year I had a personal trainer. We got along extremely well, talking about everything. He left the gym in August, and although I did send a letter wishing him well, etc., I never did hear from him.

His birthday is coming up.. I know he had a rough year, and I was thinking of just texting him a simple 'happy birthday'..

If he responds back, great.. if not, that's fine too.. I would just hope it makes him happy that someone remembered..

Kind or Creepy?.. what would you think if you got that text message?.. especially if you haven't heard some someone in a while...
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Maybe I know him better than I thought?.. I texted him.. he wrote back thanks, and questioning who it was.. I told him, and he didn't even recognize the name.. he said he'd call, but the name must have clicked, I haven't heard from him since..
Texting a guy on his birthday?
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