Do you want them in a specific map, in general or just a single unit?
To change the settings for whole game, use FinalBig to open INIZH.big, and extract find GLAInfantry.ini, DemoGeneral.ini, StealthGeneral.ini, GC_Chem_GLAUnits.ini from Data/INI/Object folder, to the exact same path in zero hour folder (I.E Zero Hour/Data/INI/Object)
Then in each of the files find the terrorist code (simply seatch for 'terrorist', and keep jumping till you hit something around Object GLAInfantryTerrorist), and find the 'Body' Module, search helps here as well.
Here's the original code from GLA terrorist
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Body = ActiveBody ModuleTag_02
MaxHealth = 120.0
InitialHealth = 120.0
End
Change these values to 240, save a voila, twice the health.
For the Map-specific code,
use this tutorial to replace modules using your map.ini file in map's folder (in my documents/zero hour/maps/mapname) - replace behavior with body ofc, also, i never used it, so im not sure it works :))
To change it for a specific unit in a map, simply go here:
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