Zimmy's un-named relative giving him a glowing review?
Yep. The un-named relative wasn't there, just like Martin's parents weren't there either. I don't see any reason they shouldn't have their say though. Narrative destroyer.
If the story gets out that GZ wasn't a white man who hated blacks, wasn't 240 lbs, didn't say Martin looked like he was up to trouble because he was black, actually had head wounds, and tried to lead a movement to raise attention to the fact that a black homeless person had been beaten... even then you'll never apologize to him.
Most damning part of the letter is George's apparent wonderment about why no blacks remember his face from the Sherman Ware incident.
Why is it a big deal the family member is un-named? Maybe he thinks the NBP might put a bounty on his head?