James,
If you could get your bro to give you the flight numbers for the outbound & inbound flights that are printed on his tickets ie. say he is flying British Airways outbound flight number 417 then the Flight ID would be BAW417 or something of that nature. The return journeys are normally similar ie BAW418 (unless flying on a different airline).
Then I believe using the RadarBox software goto the 'Alert' tab and scroll across in the window which will have the following tabs 'Mode-S, Registration, Range & Flight ID'
Check the 'Flight ID' and enter the out/inbound flight numbers that your bro gave you. Then on the days of departure and arrival home your RadarBox should I believe Alert you using one of the selected Alert options when your bro's flight is picked up (either Live locally or Networked).
Hope this helps. I believe what I've suggested should work, not tried it Myself. If this is incorrect I'm sure someone will correct My errors and point you in the right direction.
Steve R