On one hand I'd be like, great, my extended family take an interest in my kid and their activities and are even willing to take them so I can get some time to myself at the weekend, brilliant.
On the other hand I'd be like hey there Jabba the hut, if you want to eat processed shit all day that's fine, but stop filling my kid full of the same shit just to make YOURSELF feel more comfortable about your chaotic eating behaviours.
But I reckon if you said a word to the landwhale she'd go nuclear and take to the bed for a week.