He has 90 health. Carlos' Level 1 effect is similar to Ada Wong's, in that he can look at the top card of the Mansion Area before he plays his weapons to Explore. Carlos' Level 2 effect allows him take a card from his Discard Pile and place it in his hand if the damage he dealt to all Revealed Infected is equal to their health. This can only be done after Carlos explores, naturally.
These effects allow Carlos to specialize in the use of Machine Gun type weapons, specifically the two introduced in Alliance; the Russian Assault Rifle (WE-022) and the Signature Special (WE-023). These weapons, alongside the Gatling Gun from the first set, have their Ammo requirement and Damage listed as "X". This means that they' are determined by the ammo the player has to play with them, and the amounts can be designated. With Carlos, the player can Reveal the top card of the Mansion before assigning ammo. For example, if an Infected with 30 Health is revealed the player can simply assign 30 ammo to one of those three weapons, guaranteeing the activation of Carlos' Level 2. This works well for players wishing to acquire a card they recently gained, but without additional Explores gaining a recently purchased weapon can prove fruitless.
Interestingly enough, Carlos' abilities work well with the abilities of the first Jill Valentine card (based on her RE3 appearance). Carlos' ability to look at the top card of the Mansion before attacking is a great setup for Jill to decide if its best to use a Flash Grenade (which kills Las Plagas Infected instantly; and if she has her Level 2 effect, allows her to Discard it instead of Trashing it after use). Carlos ability to retrieve a card from the Discard Pile makes it easier for Jill to constantly have a Flash Grenade on hand, but this works better with multiple Explores. This compatibility was most likely deliberate on the part of the game creators, as Jill cooperated with Carlos to escape Raccoon City during Resident Evil 3: Nemesis.