Disabilty Credit Transfer

I am doing Taxes for good no of Customers since Day one Profile launch in 1997. I helped Disability Credit and transfer to legitimate tax paperers.

Mostly parents are disable and they may not hv income, so Transfer is best to Kids and kids benefit. Normal Situation.

However, i hv one client now, His wife has disability, and both are nearly 60 years. Spouse income is more so use SPOUSAL BENEFIT to square Tax to Minimum. Now as SPOUSAL AMOUNT IS USED BUT DISABILTY CREDIT IS NOT REQUIRED TO BE USED as income is not very high.

Now CRA has disallowed these DISABILTY CREDIT TO BE TRASFERED TO SON (A LIGITIMATE DISABLITY TRASFER HOLDER).

Profile is transferring the DISABILTY TO SON, but CRA OFFICER DENIED as per above contention.

Can anybody help is this LAW ok or we can help any other way to get this transfer to son??
Mohamed