Have him take Co-Enzyme Q-10
http://faculty.washington.edu/~ely/coenzq10.html
there is a neat link.
And Taurine . . .
ETA: Was he really heavy at one time?
the sooner you take CoQ10 the better it works for CHF.
It doesn't seem to have downsides. Also make sure his magnesium and potassium levels stay up.