I also had some trouble with my scoundrel early on. Wolgraff just seemed to need so much support to stay alive. What helped for me was to make him dual class witch, just enough to get the novice summoning spell. When I scout a fight with him I cast the summon, the haste spell and then go invisible. I can then use the expendable zombie to block for him so he can isolate a mob to the enemy's rear. If I save cloak and dagger he can then escape back to the rest of the group if there's too much aggro.
I'm sure there are many other ways to do it as well, and at least defensive spells always help keep the melee people alive so you should be using those all the time anyway. In general I think it's best to just stay invisible until there's a good opportunity to finish something off, rather than rush into a dangerous situation. Waiting a turn or two will fill up the action points anyway, so that when you do strike you get two or three attacks after one another.

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