My daughter ( in her 40's) and her son ( 28 years old) live with us, neither of them really speak to us, daughter "lives" up in her bedroom, working from home 4 days a week.....grandson just grunts at us when we say good morning etc..... my OH says I shouldn't try to talk to him, but when I see him each morning I always say hello and how have you been, same with daughter, I don't see how I should be as horrible to them as they seem to be to us !!
They both seem to have lost the art of conversation ( unless it's with friends either over the computer or going to the pub to meet friends )
I shall just carry on as I have been doing and plod on regardless.