Hello. The cause of the calf pain needs to be figured out prior to figuring out the best treatment. It is possible that her calf pain is caused by vascular issues, so the pain occurs due to blood vessel issues, rather than muscular.
There are numerous ways to treat tight calf muscles, from stretching to heat to acupuncture to massage, and so on. If the issue is vascular none of these will help. To help figure it out, head in with your mom to see the doctor.