You need to look into getting him a section 504 plan. This is different from an IEP (and an IEP can still be obtained should it ever become necessary.) A 504 plan will level the playing field for you son and give him safeguards and protection while in school. A 504 covers both mental, physical, and emotional disabilities. They are not based on grades or performance in school like an IEP is.

Here is some 504 information. Please feel free to ask if you would like more information!

Section 504 of the Rehabilitation Act of 1973 was passed by congress in 1973. Regulations implementing the statute became effective in 1977. For many years school districts perceived its main obligation as ensuring physical access to public buildings (i.e., ramps were installed, curbs were cut, elevators were added to multi-level buildings, rest room stalls were enlarged,
etc.). Schools were at the same time committed to compliance with special education regulations now referred to as the Individuals with Disabilities Education Act - (IDEA). With passage of the Rehabilitation Act of 1973, Congress required that school districts make their programs and activities
accessible and usable to all individuals with disabilities. Within the last several years, the Office for Civil Rights (OCR) has become active in assisting school districts in further defining “access.” The definition of access means more than physical access; a child may require special accommodations such as modified assignments in order to benefit from their education.

HOW DOES SECTION 504 DEFINE
“APPROPRIATE EDUCATION”?
A free appropriate education is one provided by the public elementary or secondary school which includes general or special education and related aids and services that
(1) are designed to meet the individual educational needs of a person
with a disability as adequately as the needs of a non-disabled person are met, and
(2) are based upon adherence to evaluation, placement, and procedural safeguard requirements.

HOW DOES SECTION 504 DEFINE “DISABILITY”?
Section 504 of the Rehabilitation Act of 1973 protects persons from discrimination based upon their disability status. A person is disabled within the definition of Section 504 if he or she:

ELIGIBILITY FOR 504 SERVICES
• has a mental or physical impairment which limits one or more of a person's major life activities; The impairment must impact the child’s education.
“Major life activities” include functions such as caring for one's self, performing manual tasks, walking, seeing, hearing, speaking, breathing, learning, and working.