Hey there Rufaro, I just came across this thread today, and I love what you're doing.
I think many of us struggle with the fact of people not taking enough interest around us, my family happily eat what I grow, but none of my siblings help out. I have, however, started teaching my nieces and nephews, and I got them tiny watering cans they can carry (I'm on the coast in Sweden, and have lots of rain that we collect in 200L barrels), and I have special small projects for them to see quick results with. Now, whenever they're here, they run out to the garden and want to water, sow or plant... and my sister still doesn't know you can't sow zucchini here in winter! So things are changing, slowly. And I leave my permaculture books out for visitors to read. One of them had an absolute "aha" moment two years ago, where he saw the change in soil structure before and after a farm was started (video here https://permaculturenews.org/2014/10/18/canadian-rocket-stove-powered-greenhouse/
) - and I gave him some comfrey to start his own farm when he left. It was fantastic to see!
Regarding your young friend, I don't either think you should give him a fence, and I know it all took place months ago, but there's an option I use with my nieces and nephews: I always ask if they'd like me to show them how to do something. I never say "let me", or "this is how you do it", because I want it to come from them. So I ask, "do you want me to help you" or "do you want me to show you how to do that", and 99 times ot of 100, the say yes. So, if you have the time, you could ask your friend whether he would like you to show him how to build a fence to keep the donkeys out, using sticks. Also, what other solutions might there be? Keeping the donkeys in a pen instead? Not something that has to be done, but it's more of an exercise in creative problem solving. It can get as silly as you want, like putting the donkeys on the roof (obviously impossible), just allow for any and all solutions and then select the best ones.
For example, you can both weigh the pros and cons of building with sticks.
It's cheap, but it's frowned upon (manual labor).
Well then, you weigh the pros and cons of that:
getting a garden started, versus people sneering at your efforts.
Obviously, you have done this whole trip and know your truths and answers, but my suggestion is guiding the neighbor into the line of thought, rather than a simple yes or no answer to whether he'll receive a fence. Helping him get in the mind frame of self sufficiency will give him so much more than a fence ever could. Since it's months since you posted about this, I presume you've already solved the problem, but I thought I'd give you a shoutout and say I love what you're doing, loved reading about it, and that the change will come, even if slower than you might initially want.
Thanks for sharing your story, and best of luck to you!