As this is a controversial subject I cannot just ask it to the majority of the women I know that bake. I make cookies for my father who has cancer and was losing weight at an alarming rate until I suggested pot cookies. I have been using Betty Crocker peanut butter cookie mix. The recipe calls for only one egg, I have been having a crumbling issue. It's too expensive to trial and error in this situation. Would adding another egg help?
Adding a whole egg would help, but you might start with adding just one egg yolk. The additional fat will address the dryness which leads to the crumbling.
You may also try other fats like butter, cream cheese, or vegetable oil.
If even one egg yolk is 'too much' for your desired outcome, you might try a small amount of half&half.
Adding more eggs will make your cookie soft and not crispy.You can add some butter but I think it will not be suitable for the disease.You add some roasted oats soaked in milk.It will make your cookies crispy and not crumble I have a oats cookies recipe which has butter in it you can look up oats cookies