Does Heart Failure Medication Cause Nose Bleed?

My father has been getting very bad nose bleeds. Severe enough to bring him to the hospital a number of times. The doctors don't seem that concerned. They just pack his nose (the last time one side was cauterized) and send him on his way. He has congestive heart failure and has a pacemaker. Could this be due to his medications (he temporarily reduces his blood thinner)? We also live in a cold climate. He has had heart problems for years so why the heavy bleeding now? Should the doctors be reviewing his medication? I'm scared the large blood clots are going to cause a stroke? Is there anything that can be done?