As he is a 14 year old boy who reads books, and has a possible future career plan, and already does 'odd jobs' like gardening there are positives to focus on. Taking him to library (or second hand bookshops or charity shops) to choose books might be another option to do with him. I agree with looking into 14-16 college options, though college might be a bit intimidating if school is. In some areas there are groups of home schooling parents, so maybe help your DD look for these in case they could help. Other things you may be able to help with are games to do with him, scrabble for example. It does not sound as though he is totally unreceptive to learning, just very anti traditional methods so it is a matter of encouraging him to think, broaden his mind and acquire general knowledge in other ways.