What happens if my mom just continues to lose weight but is still eating?

Dad lost his taste for things he used to like. Then came the decline in appetite. You should def let the doctor know. Hospice may be able to help.

She should see a doctor to rule out any treatable medical causes of weight loss, like cancer.

motherof5, as one becomes older, so do the taste buds. Thus, food that use to taste really good years ago, now have very little taste. Elders usually can still taste sugar, as I remember my Mom's grocery lists were filled with cookies, pies, cupcakes, candy, etc.

Since my parents were in their 90's, I figure they were doing something right, so I didn't say anything about all the sweets. Neither had diabetic issues, so it was ok for the sugar.

Now, my Dad did develop an intolerance to diary products which would upset his stomach big time. Once I convince Mom to stop giving Dad dairy products [Mom was from the old school where she thought a little bit wouldn't hurt... well it does] Dad was feeling more like eating. Then I introduced a product called Lactaid milk, which tastes like the regular milk, and Lactaid chocolate ice cream which was really good.

So, keep a food journal to see what your Mom is eating more of, and less of, and use that as a guide.

One of my Mom's meds actually contributed to a lack of appetite. Might want to check that.

This is a popular topic here on the forum. Basically you need to maximize the calories in what she DOES eat - generally by adding in all those extra fats and sugars we have been taught to stay away from. And nutritional supplements like Ensure and Boost were made for this.
Do you have an idea why she isn't eating? If the cause is treatable you need to tackle that end too, so check her teeth and mouth for sores and cavities and be alert for swallowing difficulties that could be causing her to choke (dysphagia). Stomach ache and constipation can make food less appealing. And if she just feels no appetite there can be medications to help with that.