Like others, op, I think you should say, "I'm putting the kettle on, John, would you like a cup of tea, or something else? Mary?
Please don't be like my mother. "Roses, do you want a cup of tea?" "No thanks mum, I've just finished one". "Oh, have a coffee then". "No, I'm fine mum, I've just had a drink". "Well, are you sure you don't want a cup of tea"? "Yes thanks mum".
Mother goes to kitchen and comes back with a tray, with a pot of tea and two cups and saucers. "I put an extra cup on and there's plenty in the pot for you to have a cup of tea, you'll have a biscuit won't you?". "I'm alright mum, I had a piece of toast 30 minutes ago". "Oh but they're lovely biscuits, the ones you used to like, I've got some chocolate ones if you want a chocolate one".
There is zero cognizance that a guest night not want a cup of tea, biscuit, sandwich, glass of wine, cheese and crackers. It is all about her needs.
Occasionally I have said on the third offer "I'm sorry mum, but what did I say just now?". Then she goes on the defensive "are you suggesting I'm going, losing my memory". "No mum, but I have just told you three times that I don't want anything else to eat or drink".
She does it to everyone and bit by bit, inch by inch they give in. Then they quietly drop her.