Two points.
1. Your friend's son is about 2,000 times more likely to be murdered by a black civilian than a police officer.
2. The claim that blacks are more likely to be killed while being arrested for a violent offense is just not true.
None of this has to do, by the way, with the fact that Floyd seemed like he was trying to keep his life on track. He was arrested. No issue so far.
The arresting officers kept him pinned to the ground while handcuffed and where one officer applied pressure to his neck. Good heavens, the best way to kill a guy hand-to-hand is to apply pressure to the carotid artery, such as during a choke hold. Seriously, wrap your arm around the guy's neck, grab the wrist of the arm applying pressure, press on the carotid artery for even sixty seconds, cut off 90% of the blood supply to the brain, and the guy is dead.