Has he even understood what it is about and is he aware of how to work on the site?
I am also unsure about that - but he already had an appointment with a construction company. Unfortunately, the problem is that we only got a neighbor so late, so he also lacks the time to grow into the role of the prospective builder. I would also consider it difficult to make such a decision now.
Just a thought: Send him the link to this thread here. That way, he can quickly get up to speed and at the same time realize that you have no ulterior motives and that it really is the best solution for all sides.