Perhaps making money out of it may not be the goal.
However working in isolation for such a long period can result in disconnect. How about asking him to do a limited alpha among a small tech group and getting their feedback?
But if his goal in saving the money was to give himself a window where he could just work on something he likes, he has good window ahead. At the end, he may just put it on Github and invite contributions and pick a day job and continue working on it on the side. The project may infact help land a job.
However working in isolation for such a long period can result in disconnect. How about asking him to do a limited alpha among a small tech group and getting their feedback?