Patchwerk has approximately 4,320,000 hit points. His regular melee hits plate for about 4,500.
Abilities:
Hateful Strike - Patchwerk will use this ability at a 1 second frequency on the target in melee range with the highest HP who is also one of the top two on Patchwerk's aggro list. Cannot be used on the main tank unless there are no other targets. Does 19975 to 27025 raw physical damage which can mitigated by armor and parried/dodged. This is about 7,000 damage on a partially Naxxramas geared tank. According to Elitistjerks.com this ability will add threat to the two most threatening on Patchwerk's aggro list though this is not confirmed.
Frenzy - At 5% HP Patchwerk will gain 25% increased Physical damage (including Hateful Strike) and 40% increased melee haste.
Berserk - After 6 minutes of combat Patchwerk will go Berserk, increasing his damage by 500% and his attack speed by 50%.
Strategy-
Both MT/OT stack on each other, dps the boss as fast as possible. Single target heals on each tank as they will be the only ones taking damage unless the OT dies.
After...Don’t Die to Frogger.