Thanks for that coment on how azimuth can be accurate, I will highlight that in my teachings in ground school.
To get back to the 1st post, it was Tragic what happened to your friend and the bottom line is... rules have changed because of it and I believe the following additional guidelines were issued by ICAO?
1. When changing flight level to avoid nuisance RA's it is good practice to reduce your VS to 1000 fpm when within 1000ft of your required Flight Level, this should stop most "I'm climbing, your descending to within 1000ft of each other vertically" RA's.
2. If during an RA another aircraft is seen, the pilot should not assume that it is the aircraft generating the TCAS RA, so it should be ignored. Easy for them to say, but it makes sense as TCAS should be aware of all aircraft in the vicinity and will issue the RA for up to 3 conflicting aircraft at one time.
Once again my sympathy to you. Pray God we learn.