If he is losing tail when first 2 adds spawn, he needs to combo faster because he probably only has 1 Savage on it. Absolute best thing to do is

Tempered Will > stand next to where head will spawn at body slam* > Fast head > Savage tail > Halone tail > pick up adds.

If he is losing hate any time after that, DPS are overgeared (unlikely) or he is derping somehow.

*This is something melee should do in general in phase 1.