Little girl's weight and health problems

I live this little girl. She's so sweet and kind. Best personality. She's always been a little heavy but perfectly healthy. This past year has taken a turn for the worst. She's had lots of medical problems. Dropped playing soccer because she can hardly breath. She's always tired now. She's lost that sparkle in her eye. I watched her the other day and when she left I realized that she had eaten her way through 12 bags of cheeseitz crackers, 7 string cheeses, 10 little juice boxes, and handful of gummies (we stock pile in the garage for easy school lunches and snacks - I have three kids lol) .

Should I bring this up to her mother? I feel like she's getting depressed. Somethings not right. I miss the happy and outgoing little girl she is.

And how do I bring it up to her mom?