I have to get in a man with a JCB to fix field drains and divert surface water if one goes at short notice. He also digs ditches and foundations and if already out will somewhat grudgingly clear huge muddy areas to a heap so I'm not wading in gateways.
I also need a fencer, a man with a tractor sprayer for weeds etc, and someone with chainsaws and ladders willing to climb and lop/fell trees and log them for me. My barn needs repair work at roof level and may need new tele poles and a wee wall built. And every spring I have to persuade the hay man to come and dig out my deep littered barn..
I find I am always back of the queue for agricontractors because they need to go to the bigger farms first and get their main income/clients sorted, with just 10 acres and things like spraying needing done in 2 lots so I can switch stock to empty fields til the sprayed weeds have rotted away, it means him coming twice for 4 and 6 acres at a time. Cost shoots up accordingly.
So if he can find a local agri college and get certificates in things like tree work, chemical spraying etc and invest in some big plant machinery, I reckon he'd never be short of work. Maybe a tractor even just to do general farmwork on contract and get himself known? But a decent mechanic is also never out of work so if that's where he fancies going, it will save you a fortune in bills too, maybe he could do a bit with AA, RAC etc on the side?