So as he would have to take a 30 minute break before 2 pm, he would not only comply with the driving hours regulations, but also comply with the WTD regulations. At 2pm he would have only been on duty for 7 hours, and has already had a 15 minute break before he had reached the 6 hours on duty.
Not sure I've understood you correctly.
He would have to take another 15 if he were to work more than 6 hours but less than 9 to comply with WTD . However , if as you say he takes a further 30 minutes it will clear his tacho and comply with WTD .
The best explanation I've read was in the RHA(big yuk!) Drivers handbook .