Against a TH7 you need to bring 2x healer, one to feed the big air mine, the other one to stay alive.
Against a TH8 you need to bring 3x healer, two to feed the big air mines, the other one to stay alive.
It is hard enough with TH8 but starting from TH9 it gets impossible, you cant bring 5x healers...
I suggest big air mine will not instantly kill healer but bring their HP to 1.

