What medical condition could make you shrink this much?

While I got divorced in 1998, I never stopped caring about my ex
in-laws. I am Facebook friends with one of my ex’s Aunts.
(We were actually friends before he and I ever met years and years ago).
At times I see photos of my ex mother-in-law who I loved dearly. She used to be fairly tall at around 5’7”. Now she is shorter than the Aunt I know who is 5’3”! I know she has some serious health problems, but I don’t want to ask for specifics. What could be causing this? It’s alarming to see. She is 70 years old. I don’t think this could just be osteoporosis.