I experienced this in the past. I had to keep reminding myself who was the adult, me or him. Me, presumably. Don't give up or lose hope. This worked for me but I'm not saying it will work for you so ignore any or all of the strategies we used. My husband gave him lots of attention which we assumed was what it was all about. I gave remote attention and stuck to, here's a drink/biscuit - whatever - no choices or discussion offered. Lots of smiles and fond looks though, very important. At goodbye time I just waved goodbye no kiss, nothing. It is/ was very hard but I think it is a power thing, and there are now occasional thaws to which i respond with normal conversation. We have reached the point now when I have said, I won't kiss you goodbye but I'd like to shake your hand, no choice offered and this has been accepted. He is not our only grandchild so I do have more positive experiences to comfort myself with.