Welcome to HCM.
Since your mother had valvular lesions which required replacement and to prevent thrombus
forming on the replaced valve, she was started on anticoagulant
Anticoagulant drugs do carry the risk of hemorrhage in unwelcome places, but stopping the therapy puts the patient into higher risk, so a balance has to be achieved. Best way to do is by monitoring prothrombin time
so as to keep it within fairly safe limits. The best judge to do this is your consulting doctor who knows the patient's tolerance level as well as the risk involved and he has to take a calculated risk.
I suggest you follow the advise of your doctor.
Wishing your mother all the best.