2 is very young unless an emergency. Perhaps he has stayed with other GM with mummy there and she knows his routine well. My DGS2 is almost 2 and we have him 3 days a week but not overnight unless mummy is there. He is happy to nap for 2 hours but is still breast fed at night and first thing in the morning and looks for mummy so too soon for him.
You have your grandchild all day once a week and you are on here moaning about not having them overnight?! Your DIL or son can pick up their child early or miss weeks or cancel days, as long as they have the courtesy to let you know, for pretty much any reason. As the child gets older they are going to mix more with their peer group too, you really mustn’t get too attached your routine. You sound incredibly entitled, even if your grandmas behaved as you are doing, you should be aware that it’s not the norm, and unless you are brilliant at keeping a lid on it around your DIL, she probably finds you very difficult.
Loulelady is spot on. I also suspect you haven’t taken in the responses from your op otherwise you wouldn’t have needed urgent advice because you would have realised how utterly ridiculously your expectations are.
Your next post will be because son and dil have had enough of your behaviour and have cut back visits- if they do it’s on you I’m afraid.
It’s the parents’ decision whether or when you see GC. I can’t imagine why you want him to stay longer or overnight alone unless you see the child as some sort of toy and you want to play mummy. You see him quite a lot anyway, don’t fret about what the other GPs do. It’s not a competition.