Thanks for posting your query.
Do not worry, your sister can get married & lead a healthy happy life.
It is an autoimmune disease
, which means the body's immune system mistakenly attacks healthy tissue and is also a long-term disease that leads to inflammation of the joints and surrounding tissues. So she needs to continue these Disease modifying anti- rheumatic drugs(DMARD) to prevent recurrence of disease.
Your sister needs your support, life style modification, education about the disease, regular exercise, and physical therapy
to fight the disease better.
Hope I have answered your query.
Wishing you good health.