The Little I Know:
You obviously do not know a lot. Bipolar Disorder is untreatable. It can be controlled by medication. As far as Borderline personality goes. A person can be treated and cured. It takes 7 years of DBT (Dialectical Behavioral Therapy) and intense work to be officially cured. Medication helps stabilize the moods so it is “easier” to focus on implementing the skills into daily life. The therapy teaches you how to have healthy relationships, survival techniques and being mindful of your surroundings. It is true it is extremely difficult to live with someone if they are not taking their meds or going for therapy. It is still hard to live with somwone is in the middle of therapy as there is lots of trial and error stabilizing them on the medication. As well as he/she learning the ropes and rewiring the brain to communicate properly and build a life worth living.