Thanks for posting your query.
Normal iron level is less than 12 grams / 100 ml in women. 500 is far more increased and refers to hemochromatosis
which is common in men but may occur in women, however it appears late in women due to loss of iron through menstrual cycle. Hemochromatosis can be genetic or acquired and may present withchronic fatigue
,arthritis/joint pain,hair loss,diabetes,abdominal pain
,swelling,frequent infections,heart problems,cirrhosis or liver.
You need to perform labs like transferrin saturation, serum ferritin level, and liver function tests.Liver biopsy
and MRI may be needed.
It can be treated by therapeutic phlebotomy, iron chelation therapy
and dietary changes.
I advise you to send your mother in law to doctor for further evaluation.
Hope it helps.