soutra is right, this is using up valuable energy, so try to just let it wash over the top of your head.
They are her friends, not yours, so you don't have to see them, although if they are nice people they will be concerned for you rather than nosy. I can understand you wanting to keep it to yourself.
Can your DD have a word with her granny and suggest she stops fussing but does do those things you would like her to do. She is anxious about you, which is natural.
Perhaps the hospital can give you a leaflet about lowered immune systems which you can shove under her nose give to her nicely with bits highlighted about what you shouldn't do and things to avoid..
Deep breath, big smile (swear to yourself if you want to) 