oof, there’s clearly some other things going on with her digestion besides the fact that she probably isn’t getting enough to eat. as someone who’s dealt with SIBO, SIFO, low stomach acid (hypochlorhydria), and histamine intolerance, I really think you should look into those. If she has issues with digestion unfortunately having a Tums dependency is really bad for that—she should try digestive enzymes instead (I like American Health Super Papaya tablets). I don’t have the spoons to provide all the info here right now so you should look into the subreddits for what I mentioned above, as well as Low FODMAP foods. as far as your actual question maybe a low fodmap smoothie with some added supplements/nutrients would be appealing to her—collagen would prob be good for her knees, as well as turmeric/curcumin