That's the minimum requirement for a qualified development under federal law. States and local communities are free to set higher standards. In addition, if the HOA doesn't enforce the contract as to these owners, they will likely be estopped from enforcing as to other homeowners, so there is no way to legally maintain the character of the community once they start down the path.
As for the child not being of school age, since he was probably exposed to drugs in -utero (he's 3, and has lived with his grandparents for 3 years, suggesting that the mother's drug problem pre-dates his birth), he's probably got physical or emotional conditions which could qualify him for pre-K services. See the Pinellas County School syterm page for pre-K programs:
http://www.pinellas.k12.fl.us/ . So there is a fairly good chance that he is of school age.
>> he’s probably got physical or emotional conditions
Would this qualify the child as being handicapped? If so, the community could possibly be challenged according to discriminatory clauses part of the code cited earlier.