Unlike the main characters that have a full line of 'FF', followed by a second slightly more than full line, at least in this case the first 'line' is not a full one. I think you pretty much have it, but are likely at the second line, thinking it was the first (from the 'Start Agent Save' just scroll down a couple 'pages' until you get to the first line of FF that overlaps itself.
Alternately, in your file Brian's locations is (X = E9 06, Y = 38 0F), so you could just search down for the next hex instance of 'E9 06 00 00 38 0F'.

The first part of Brian's position should be changed from E9 06 to 40 08, or so (the Y value is fine).

I've also replied to your email.