if your brother has two accounts, (i assume one would be qf) its probably best if the second is aa or cp. then he could do:

jfk-lhr on aa - $400
lhr-man on ba - around $150
lga-yyz on cp - $150 web $190 non web (book cp livery only)
man-ams on cx - $330

same less than $1000, but he can pick up three carriers on one trip to europe.

if his second carrier is ba, transatlantic could be jfk-man on ba, and then aa web saver jfk-phi or jfk-bos usually are around $79.