He would be able to do only part time CPT from the get go. This is capped at a max of 20 hours per week. Once 9 months have passed, he can do full time CPT of 40 hours.
Where are you located?
"Practical training may be authorized to an F-1 student who has been lawfully enrolled on a full time basis, in a Service-approved college, university, conservatory, or seminary for one full academic year. "
Email me if you need specifics.