The thread is "how to help your healer", not "how non-healers think healers should heal". With respect to healers healing themselves vs. their groupmates: a healer can't heal you if he isn't alive.
Your example is a pretty rare case in my experience. The healer that's supposedly healing himself when he's at 80% and you're at 20% might be doing one of the following and you'd have no way of knowing:
1) He might be healing somebody else who's also at 20%.
2) He might be out of LoS or Range relative to you (very likely in my experience).
3) He might be actively taking damage and only at 80% because the healing is keeping him there (and he would die in seconds if he stopped healing himself).
4) He might be healing himself because a healer whose health is below 100% becomes a target for opportunistic DPS very quickly.
5) He might be unable to find you in his operation frame because your Legacy name is displayed as a surname (or because players occasionally don't show up in the operation frame at all).
6) Even if you see his health going up, that doesn't mean he's self-healing or using heals that could be used on you instead (http://www.torhead.com/ability/b39iOqk/adrenaline-rush
If you do have a way of knowing, then you should be paying attention to what you're doing instead of watching everybody else's health and
Edit: Also, if you have guard on a healer, he should be following you, not the other way around. You definitely need to tell him you're the one who's guarding him.