I'm think a couple of good candidates for truck patching, and limiting weight around 1500 lbs. would either be a Farmall Cub, or Allis-Chalmers G. The problem with the new CUT's is they are not width adjustable for row crops. Most like to plant either 30" or 36" rows. Impossible to do with most CUT's. Implements & parts would probably be more plentiful for the Cub. Neither overly blessed with power, but plenty for what they are going to be doing, and what the tractors were designed for. And way ahead of a walk behind tiller..!! A newer Cub with Fast Hitch would make changing implements a lot quicker also. Cultivators are still a PIA to mount & remove, but do a great job.
With the up and coming CSA's and organic farming, these smaller tractors are getting gobbled up. Some are even converting the Allis G's to electric.
If they could use something in the 3,000 lb class, a buddy of mine is doing 5 acres of veggies with a CA Allis. It is dedicated to cultivating, and pretty much it's job, plus switching out 4 shanks to use hillers on his potatoes. I'm not much of an Allis guy, but that little tractor is sweet..!!
You may also inform them about checking into using feed grade corn gluten as a weed preventitive. Use it as a post emergent organic herbicide. You can buy organic Preen, which is 100% corn gluten meal, @ around $15.00 for 5 lb., which cover 250 sq. ft. I think Ortho makes a similar product which costs around $28.50 for 50 lbs, which would cover 2500 sq. ft. OR..., do as I did this fall with a little experiment grinding corn gluten feed pellets into meal at a cost of $15.00 per 100#. So far the test plot is I'd say 98% weed free, since the 2nd week of August. Will definitely be using more next year in all of the garden..!!