ongoing issues after open heart surgery

After 2 open heart surgeries and 3 pacemakers,( 2 after surgery), my husband has 2 major issues I am concerned about. First he has begun to have balance problems; it appears if he walks every day it is not as severe. Othewise he begins to tip to the right or left. Any suggestions?  
Additionally he burps and has an unsettled stomach almost every day. The burps are followed by coughing and it sounds as though he is going to throw up but he doesn't.
Any ideas as to what is happening, and any suggestions on how to handle it? He does not have a great appetite

[Cleveland Clinic]

The only balance issue that could result from having had open heart surgery may be related to an intraoperative ministroke.  This of course would have to be proven.  The fact htat he has a PPM precludes him from getting an MRI, but sometimes a CT scan can be helpful.  The other thing to keep in mind is that not infrequently, various medications which he may have been started on could also cause balance issues.  This is something you should talk to you his PCP about.

As far as the GI symptoms, they sound like reflux, or an esophageal hernia.  Medical therapy is usually most effective.