It depends on where he is, where I am frost level is about 3ft down
and - 22f at a max, 50f water might not make it before it froze.I
think hiring a kid with a shovel has to be cheaper.

around here few kids will shovel, and those who do want a fortune,
after my slip and fall accident i tried to hire some to shovel my 12
by 50 foot front flat driveway. with 3 inches of snow kids averaged 60
to 75 bucks, nice soft lightweight snow. a guy with a plow wanted 125
bucks.heard later kids quote 1/2 of plow cost

if initially installed properly the underside of thje slab is
insulated with foam, so heat is directed upwards.

this is the ideal use for a dedicated tankless water heater, filled
with anti freeze and circulated by a pump.

ask some neighbors, if theres is heated they may be able to refer
someone.