Can I claim my son as a disabled child?

I have a son who is 12 years old and is adopted.  He is considered disabled because he has severe PTSD an ADHD.  He gets income each month from the state because of his adoption.   Can we claim him as a disabled child?  The money he received from the state pays for some of his care.  We also get mileage reimbursement from his school due to his disability he can't take a bus to his special school with the other kids.  Can I also claim the mileage?  Thank you