I’m a dentist specializing in airway prosthodontics and sleep dentistry. Restless leg syndrome is considered a sleep disorder. If your mother has not had one, I would recommend her having a sleep study. Her physician can refer to the proper sleep clinic. There are some sleep disorders such as obstructive sleep apnea and upper airway resistance syndrome (UARS) when properly treated can reduce the rls. Does she snore or breathe through her mouth while sleeping? There are some simple solutions to promote nasal breathing such as nasal dilators (Mute) and Buteyko mouth taping.
Brian Dennis DDS