He still has a chance to condition himself.
For the next two years - ride 30,000 miles/yr. No jokes.
Easy miles, hard miles, intervals, sprints, climbs, etc... with regular rest.
Hone in on your cornering/descending/drafting skills - ie. following fast group rides everywhere.

By then you should be able to blow through Cat5 and 4. From there - you'll REALLY know if bicycle racing is for you.

-simplyred