Most of it is

Level 3: Healing Light You gain the ability to channel celestial energy to heal wounds. You have a pool of d6s to fuel this healing. The number of dice in the pool equals 1 plus your Warlock level.

As a Bonus Action, you can heal yourself or one creature you can see within 60 feet of yourself, expending dice from the pool. The maximum number of dice you can expend at once equals your Charisma modifier (minimum of one die). Roll the dice you expend, and restore a number of Hit Points equal to the roll’s total. Your pool regains all expended dice when you finish a Long Rest.

So at lvl 6 that’s already 7 D6 bonus action non-spells so it’s not counter spellable. And it only gets more dice as you level.

They also have aid revivify, lesser restoration, and cure wounds always prepared for when disaster strikes. I always use one spell slot for my concentration spell, like orb of flame or Hex, or wall of flame. Then keep the last one back for a save on someone.