I think his problem are raid not moving when Infernals charge?
Ok first clean up what's problem in your case. If Infernal charge DPS X - explain them that that's not problem of Tank Y - no matter class.
Portal spawn: (Kill it fast on HM)
Tank building aggro.
DPS deals some damage.
Infernal sets itself as a ball charges random target, and start to cast hellfire.
Use some addon to check what's your raid dying from:
If your raid is dying from "swing" damage - it's tank problem
If your raid is dying from Fel Streak + Fel Inferno damage - it's raid problem - they don't move when they are supposed to.
On pala issue, my best pala healer is beaconing MT usualy, so when he have to spot heal someone he don't lose heal on MT... but creative and proper usage of b(e)acon diversify imba pala from poor pala and cannot be made general rule "who to beacon".
Mookey | GM of <RISE> Xavius [EU]