Is this is a stay at home and rough it out kit, or a BOB to get out of dodge? What natural disasters might be expected? It helps to know why the kit is needed.
Make sure to check out the
Frances thread. A couple things from that thread that come to mind include having a generator and a solar shower. Don't forget personal hygiene items like baby wipes, toilet paper, and "female" hygiene items. If your going to put in candles make sure there are plenty of them. I would get her a small backpacking stove and fuel so she can still cook.
If this is a BOB you might want to add a tent and sleeping bag. If it's a stay at home kit your mom probably has enough blankets to not need the emergency blanket. Also, make sure there are several trash bags. I would also throw in a wool cap and a pair of leather work gloves.
If this is a "power out" kit does it really need a signal mirror? Most people have a signal mirror so they can be found. Your mom already knows where she is, at home. I think the compass might be right up there with the signal mirror in usefulness to your mom. I won't argue with the whistle except to say she should have it on her at all times.
This post maybe a little disorganized. I was just typing as things came to mind. Also, I'm still new here and I'm sure the "experts" could pick apart your kit better than I can.
Robert