Help: What career opportunities after 6 years working on ABS (Asset Backed Securities) analysis and valuation?

Hello everyone!

I am seeking your advice for a friend.
He has been working for the last 6 years as a quantitative analyst on ABS (valuation, modelling prepayment and default rates...).
That's his only professional experience.
He has two degrees: one in mathematics and another one in risk management and finance.

The problem: he is looking for another opportunity, and refuses to work on ABS.

As he has good quantitative skills, I am almost sure that he can be very good at any "quantitative position".
But what kind of position? When you have worked during so many years in a specific field as this one, can you move easilly to another one?

For those of you who have worked on ABS and who have moved to other positions, what are you doing now? Was it difficult to land your new position (please respond only if you are still working on finance)?

Thank you :)

Mona