The Union Force MC's are the most problematic and dangerous bindings I have come across. I bought them last year. The orange screws sheared repeatedly. I lost a toe strap freeriding in the backcountry in the Arlberg due to a broken screw. The UK dealer said it was simply a 'bad batch' of these lightweight screws and gave me 3 spare screws. The screws kept breaking and I ended up hunting for parts that fit in different snowboard shops every time it happenned. My baseplate broke last week and I had to organise rental bindings in 2 ski resorts I spent the holidays in. The baseplates have a lifetime warranty but I will be switiching to another brand. I can't speak for other Union bindings but the Force MC's are not safe.
Moreover when I emailed the company about these issues I got no response. The only time they got back to me was when I posted the above on their Facebook page, and rather that offering a solution implied that I had not given them opportunity to resolve this matter.
I suggest you save yourself some hassle and ensure that your son enjoys his time on the mountain rather than having to deal with a company that talks about quality but has no idea what that means.