Good luck Joey. Hope the pills don't kick his ass in the long term.
An auto block belay backup is a French prussic/ valdotain (not VT) tied with a loop of accessory cord below the rappel device, clipped into the leg loop. Your brake hand keeps pushing open the auto block when you are in control, and if you lose control, letting go of the rope, the AB grabs, and forces the rappel to lock up. This hitch is easy to release after loading, unlike a prussic above the rappel device, which then can't be extended away from the body.
Extending the rappel device away from the body with a life support sling is very good for control and to keep shirt and hair from entanglement.
This let's you get both hands on the rope. If you wear gripper gloves, this allows room for hand over hand, rather than burn off the gripper latex. This let's both hands ride on your lap/ legs comfortably, and symmetrically/ ergonomically, rather than the typical one hand up and one hand down. Stiff arming the brake side to a degree.
A Ground belay, aka fireman's belay, means that a ground person holds the tail of the rope, ready to pull down and arrest the fall. A munter hitch is in the braking position with the tail exiting the biner upward. A FB will need a lot of force, possibly fighting the climber pulling up to lock a minter hitch in the Non braking position.
This comes from rock climbing where 100 and 200 for rappels are common on long routes.
Furthermore, if you don't have a prussic, and need to stop hands free, take the brake side, drop it down the outside of your legs, rather than between ( let's say over the right leg), bring tail around your right hip/ thigh, under your butt/ top of hamstrings, up over the left thigh and down between your legs. Wrap left thigh as needed, maybe 2 to 3 wraps. It's locked off. When ready to proceed, hold the rope in the regular braking position with two hands, flick off left leg with some leg motion. Head down.
There should be a rappel technique thread.
If on spurs, just keep your spurs and lanyard on, and let the groundie work on other stuff, imo , as practical.