The all-in: if he is a newish player, it could inidcate he is playing his hand strength. If he is not newish, it could indicate a turned flush draw\straight draw, and he is semi-bluffing
The immediate action: less likely to be a complicated draw, as he would have paused for a second to figure it out. Seems like he had his mind made up before the move
The standing up: could just be mimicing what he sees on TV, could be excitement, could be nervousness.
Leaning in: Indicates a lack of defensive or protective body language
Taken as a whole, I think he is medium strong(TPNK, second pair) , but the turn did not hit his hand. He is overplaying his hand because you did not raise his flop donk. He thinks he is ahead, but isn't sure.