This Guardian piece delves deeply into his radicalisation.
It briefly mentions the death of a gang member friend, but no suggestion that it was race related or that it was in any way connected to what he did.
a href="https://www.theguardian.com/uk-news/2017/may/28/salman-abedi-manchester-arena-bomber-radicalisation">https://www.theguardian.com/uk-news/2017/may/28/salman-abedi-manchester-arena-bomber-radicalisation