As a spouse of a Learning Disabilities teacher for 18 years, can I offer some comments.
First, being labeled LD means the child is of at least average intellegence. Otherwise they would be labeled Mentally Retarded (MR).
Second, the father states that he has processing problems with verbal communication. Perhaps you can communicate in writing. Even in a BOR this can be done.
Third, try talking to the childs Special Ed teacher for tips dealing directly with his needs. You may need the father's assistance to facilitate this due to privacy issues.
Fourth, You mention the chi