Recently I've been reconnecting with an old friend from university and we've met up a few times in public locations for coffee etc. We've been getting along really well but I've noticed one aspect of his behaviour that comes across as very odd. Whenever he sits on a chair to eat/drink, he props himself up so that his feet are also on the edge of the chair and he picks at food rather than eating it "normally".
People around us have noticed and I've seen some people pointing and quietly laughing. One of my other friends even asked me why he "sits and eats like a monkey". Like me, he is on the autistic spectrum and can be a bit socially "blind" so I'm not convinced he even noticed. Nevertheless, I think this is something I want to bring up with him.
My question is how best to approach the topic. No one likes to be told that their behaviour is weird but I think it's better that he be made aware from someone meaning well than being made fun of. He was bullied at university due to some of his other behaviours (most of which he has been able to correct or subdue) which really harmed his self-esteem and caused him to withdraw, another reason I want to approach this carefully.
My intent more than anything is to make him aware of his behaviour. If he already is and the potentially negative attention doesn't bother him I'm not going to push it further. I just want to give him the chance to correct his own behaviour if he is unaware.