If you can get a copy of the program from his hooding ceremony (usually a very elaborate document), you could have it professionally matted and framed along with a little tag on the frame with the date. If he has a wife, she could probably help spirit away the program so the PTO could have it done. Or, you could put in a call to the university and ask to speak with the administrative assistant who manages the doctoral students to see about getting a copy.
The principal of our school recently received his doctorate and our PTO decided we would like to present him with a gift, but we don't know what to give him. Any suggestions? By the way, he is a wonderful principal and is very involved with our children and our PTO.