Hi If your mother is getting corns repeatedly. She might be having Neuropathy ( problem with nerves in the feet ) very common in diabetic patients or it can be simply because of an improper foot wear. If she is diabetic please get a screening of her nerve sensation is in the feet and her foot wear needs to be examined. Traditionally measures corn caps can be used if she is not diabetic , if she has diabetes please don’t use them. but they don’t resolve the problem permanently. The root cause has to be dealt with. She might need some topical moisturising creams and change in foot wear

They have to be removed surgically. Consult a surgeon.