There are no set themes or artists that have to be studied, it's totally up to the teacher what is done on the course.
If I had a student like this, I'd offer the teacher that he could find images of icons, family members, people important to them. Either taken by him or by someone else, as if they're expected to have photos of themselves, then it can't be the photographs that are important as that assumes someone else takes them..
Portraits and having the whole class do the portrait is a great way of bring able to compare and rank order the work for a mock exam, but personally I'd rather set a personal project or a project where they choose from a number of themes for a mock exam, as this more closely mirrors the actual exam, component 2. The final piece only really covers about 2 of the assessment objectives, and drawing is only a tiny part of the course. It's not holistic in the way a proper project is, which is what the grade is based on.
However, with the year we've had, I'm not surprised they're going for something simple.
I'd ask exactly what criteria they're marking on, if it's observational skills, portraiture and working in a timed way, then a photo of anyone would do, can't see how it needs to be him.
Or, photos as a child/baby? Although this can be more difficult for proportion...babies faces are tricky.