Enforcing better care for a special needs child.

[DeterminedDad35]

I need better understanding of how to enforce better care for my special needs son by the custodial parent.  My son is a high functioning autistic 14 year old.  Unable to keep up with the regular classroom environment, he's been in special education classes since late elementary.  He's currently listed as being in the 8th grade but is on a 1-2nd grade level.  His mother does nothing to my knowledge to further develop his independence beyond this special education public education (no third-party therapist, psychologist, sociologist, schools for autistic children, etc.....).  I live in an environment which can provide many resources to grow his abilities and independence, but his mother won't allow him to live with me.  What can I do to enforce her to do more or to grant me custody so I can?  Thanks.