It also stops him dying after Three Card Bounty, obviously. In fact, he's essential now and not in the NCR faction. After all, he is just a merc.
After talking to him for a bit, you'll have the option to hire him. Just pay him some caps and he'll tag along.
Also, feel free to take a cram opener, he has a spare one now that the player can't take.
PS: like my other companion mod (the robots one), this has no wheel or JIPCC&C menu compatibility, and it never will.
I hate the wheel and only have JIPCC&C installed to remove it, and never use the mod's custom menu thing.