Being a long time like this doesn't rule out infection, just that it could be present in the skin or shallow tissues rather than in the deeper tissues. Does she spend all her time sitting or reclining, or does she get completely horizontal at rest and do a fair bit of standing, bending and walking during the day? Is she diabetic, or possibly undiagnosed type II? Is there any occasional blood leakage from the red & blue area? Is the skin is poor condition on lower legs? If you asked her this stuff would she tell you the truth? People her age often fear being taken away from their home and never being able to return. With good reason unfortunately.

It could be something fairly easy to fix with medication and compression socks. Or it could be something more complex and difficult to treat like peripheral arterial disease or advanced complications of diabetes. Or could be a bunch of stuff I know nothing about.

In my unqualified non-medical opinion: The symptoms described could mean serious problems. To know one way or the other, she requires diagnosis by a qualified, non-ageist, non-sexist medical professional. If she has no fever, she should keep her legs above her heart to reduce swelling and discomfort until a proper solution is found; start looking tomorrow. If she has even a low-grade fever, she should be taken immediately tonight to emergency medical facility to rule out an infection which, even if "only" in the skin, could easily spread elsewhere in the body including to heart valves (all the faster by raising the legs), which is very difficult to treat.

Anyway that's what I'd want to arrange if it was my relative, friend or neighbour. The person also has to be willing and, in the good ole yew ess of eh, money must be available or raised. Best of luck!