I didn't say he was incapable of checking he us perfectly capable of checking but I do our family calendar in this house so he doesn't need to. (My choice)
Are you serious? You do know yiur husband is an adult. Why does everything have to be organised by you. You do realise that you are moaning about sil insisting she does all the organising and you do exactly the same.
You dont have to go! If Mil moans just say 'well sil arranged the date with dh and he forgot to mention it. By the time i knew it was too late'.
Of course if she discusses a date with another adult, that date is fine. If it mrans only he can go. Only he goes. If it mrans non of you can go, tough.
If your dh can not pull himself together to say 'i will call dw and check'. Thats his is fault. Not your sils.
You need to get your head out of
your arse regarding your sil. Ger child being at nursery is no business of yours.
Its clear you treat your husband like a child and expect everyone else to. You intensely dislike sil so blaming her for this.
If i were her i would refuse to arrange stuff with you. Especially if you went behind my back and attempted to change arrangments i have made because my brother couldnt act like an adult.