If your husband wants to keep heart size and function normal, he should not drink to excess. One or two drinks of alcohol a day has been considered helpful, but some people cannot stop at one or two drinks so that may be a problem.
Some PVC's should not be any concern. An enlarged heart can cause a rhythm disorder.
We are not sure of the cause of the cardiomyopathy. He was in a rapid atril fib -- for how long we don't know , they cardioverted him and he has been in sinus rhythm since then -- the meds have brought his heart back to normal size and function . He had multiple runs of VT, and now has some PVC's...
The medication you present dialte blood vessels and reduces the workload of the heart. If the heart was dilated due to high blood pressure (constricted vessels), then stopping the medication may return the heart to its pathological state.