Okay,i know the problem.. Generally, if a Pokémon is burned, it will lose a set amount of HP every turn, and its damage dealt by Physical moves will be halved.So give it a toxic orb and then it will do double power.Your idea should work then.
This is what Bulbapedia says when using facade:
Facade inflicts damage. Its base power doubles from 70 to 140 if the
user is poisoned, paralyzed, or burned. Burn's effect of lowering
attack is still applied, unless the user has Guts.