Ours doesn't get mini cornettos or and other icecream unless he eats his dinner and then he has a scoop of vanilla (which I admit is his favourite) or maybe an ice lolly when we are out. We do do lots with him though, look out for free/cheap events to go to, lucky enough to live quite near the beach so go there or to the park or for a walk in the wood where we collect cones or leaves and so on to make thing with when we get back. We play games and read together a lot, though at six he is an excellent reader, play ball in the garden etc. He likes the fact we have time to devote just to him and always wants to come to stay if he gets the chance for a weekend or a week. I don't think the things they are given or the treats in terms of sweets, ice cream etc it is the one to one time and fun. Is the Amazing Grandma a character in a book? How old is he? Sounds as if he is anxious about being away so there may be a reason for that. Don't beat yourself up about it, we can all only do our best.