If the healer keeps him up though, I'll just exit and add said DPS to my ignore list.
You should whisper the healer, because a decent healer will keep him up. No reason to punish the other dps and the healer who are doing their roles. Either whisper them or vote kick.
Unless someone says something, I am sorry, but I am going to heal. As a healer keeping everyone on their feet is my job, so unless the tank tells me otherwise that is what I am going to do. However, if the tank whispers me, then I may not heal the dps, if I agree with the tank and I have been on plenty of HMFP where dps pulled everything. I usually whisper the tank and ask if they are ok with that. I am geared well enough I can take 2 dps and a dps companion through many HMFP so I can deal with dps pulling, but they really need to learn the proper what to play. Instead when they get a fresh 50 healer that is most likely better than me, just not geared to keep up, they kick the healer saying they are bad.