Hi T.,
I've been a special education teacher for four years, and am now at home taking care of my son. I think it would be wise to request an assessment of your son to see if he has a learning disability. This will allow him to access invaluable resources for the rest of his high school career, and will also allow him to access resources that colleges provide to students with diagnosed disabilities. A parent can request an assessment at any time, and a request from a parent is rarely refused. This assessment will not automatically place your son in special education, it will be used as a guide to see if he qualifies and will provide great information for you guys to know the exact areas with which your child struggles and what can be done about it - this information will be shared with you whether or not he qualifies.
If you are reluctant to have your son assessed, which I understand many parents are, it is never too late to look for extra help. The biggest barrier to tutoring that you will find, however, will be your son. If he doesn't want to improve his reading, he is going to resist the tutor and will not be able to learn as well. If you can sit him down to discuss his difficulties, and hear from him that he wants to become a better reader, this could be the first step toward accessing extra help. I have been tutoring students struggling with reading for 6 years, and the students that don't want to be there don't learn as well as those who want to become stronger readers.
Your son's definitely old enough to talk to about this issue. Ask questions about what is hard for him, and why school might be frustrating. And don't be afraid to ask a teacher or a trusted member of the school staff about referring your child for assessment.
Best of luck, and please send me a message if you have any questions about this process,
Amy K.