My 4 year old has always struggled with other adults. Even family, he won’t say hello to them and if they look at him he hides or makes a face or gets upset. He does tend to warm up a bit after a while but it takes a long time and will still be the bare minimum and it’s frustrating. We have talked about it a lot and I say to him it’s kind to say hello or wave, I won’t force cuddling etc but to at least acknowledge people and not get so upset! He’s good with other kids, he will go off at soft play and play with kids he’s never met but adults he is so different with.
Also if I’m not with him like at nursery or when he goes to his uncles (the one he ignores when I’m there!) he is fine and they say he’s chatty.
I dont know what to do about it? One set of grandparents (my PIL) now make comments and it’s starting to aggravate me as it’s hard enough!!