To give the man his due; his idea may be altered to make it more feasible.
Instead of shuttles and tethers, why not
simply redesign a cone-shaped "Orion"
crew module, crew of 4, fitting it with nonporous parachutes
and large gas-bags to cushion its landing on Mars?
A large habitation and supply modules will await them on the surface.
That cone-shaped crew-module could be attached
to a linkage of a 3-4 ESA, "Jules-Verne" type cargo craft
on the trajectory to Mars, and there are several HLV's in the works
[design and planning stages]
that can send up several propulsion-modules to LEO to link up
with the cargo and crew module assemblage?