Rows are not numbered sequentially. Plus the row numbers are changing in a few weeks.

Row 26 is 5 rows behind the window exit; row 28 is 2 rows behind that. The seat maps on co.com are accurate.

As for how to explain to your boss that you can't get him an aisle seat, well, good luck with that. Unless you are in the bulkhead or in A or F on the exit row (formerly 14, soon to be 21) there is no extra legroom in any row on that plane. So it doesn't really matter if he's in 8A or 26A. It is going to suck.