Let her sit and scroll. Parts of her body probably hurt and it is common for older people to talk continuously about food: prep, prices, recipes, the next meal, etc. If you plan anything, plan it with your children’s pleasure in mind- she can sit on a bench. You can’t make someone a loving, attentive grandmother. If she was a loving, attentive mother, consider yourself lucky. Kids are exhausting and draining. Accept her as she is, flaws and all.