Case study 3 - possible approach to stage 3

One possible approach is:

Arrange to meet with him again.
Discuss the outcome of the above training - which you discover he has not attended due to lack of time.
Arrange a discussion with the mentor.
Book him on the training again with warning that he must attend otherwise you will have no choice but to institute disciplinary procedures.
Put meeting summaries in writing.

Your Faculty/Service HR Manager or Officer is available to support you through this process.