Outside of using Lost Souls set, it’s not realistically possible to keep skeletons alive end-game.
This build is designed primarily around flash-farming Crucible, where you and your pets get extra toughness from the crucible buffs. It can of course manage to do campaign just fine, but you will need to resummon pets from time to time. If want a more general purpose Ghol Cabalist I’d recommond this thread, although if you’re playing HC you might want to use an Ishtak based devotion setup instead.