I released version 3 of the GBaddy not that long ago (you can find it
here). Just figure I'd point that out in case you didn't notice since you should be using the most recent version of the script before changing it around.
As for wanting the baddy to work with custom systems, you would have to make alterations to the damagePlayer() function (particularly the setcharani("sword", ""); line). You can place your custom health variable under that line and it should deduct straight from it but the system will still remove from player.hearts due to the baddy using sword.gani, so you'll need to address that. The onCounter() event also uses a setcharani("sword", ""); line so keep that in mind as well.
Edit: Looking back at it, the script as a whole could use a complete overhaul (especially with there being a lot of redundancy), but investing anymore time in it would be a waste; nonetheless, it's complete enough for what it's worth--a learning tool to help get you started, not something to be used on a server without major modifications.