On the day your intellectually disabled child turns 18, give yourself a birthday present – put him or her on the Section 8 waiting list. The Section 8 housing choice voucher program is the federal government's major program for assisting very low-income families, the elderly, and the disabled to afford decent, safe, and sanitary housing in the private market. In the Boston area, it usually takes eight to ten years to get a voucher, starting from the day you first submit the pre-application.
Once a person obtains a voucher, the federal government will pay part of his or her rent for life. So the sooner your child is on the list, the better.