Can a rehab doc delegate wound care to a physical therapist?

Yes: Yes as long as they (the rehab and physical therapist) has the appropriate training and expertise it's fine. Your primary care doctor should be kept in the loop as well.

He can : A physiatrist (rehab doc) can refer wound care but as a physiatrist and wound specialist i would prefer they refer to wound care unless they know the wound skills themselves and give orders other than "eval and treat" to the therapist.