In Tangerine, how did Luis die?

In Edward Bloor's novel Tangerine, Luis Cruz is killed by a blow to the head from a blackjack wielded by Erik Fisher's friend, Arthur Bauer. 
The head wound doesn't kill Luis right away. Luis had an aneurysm, which is a weakening in the wall of an artery; it causes the artery to stretch out, making it susceptible to bursting spontaneously or in response to an injury. He was hit on a Tuesday, and six days later, he was dead. 
Paul Fisher, the narrator and younger brother of Erik Fisher, saw Arthur Bauer assault Luis. Luis had shown up at football practice looking for Erik. He was there to confront him about hitting his relative, Tino, in the face. When he finds Erik and tells him the reason he is there, Erik directs Arthur to take care of Luis. In response, Arthur fishes a "blackjack" out of his gym bag. This is a sock filled with lead. He uses it to hit Luis in the side of the head while Erik keeps moving, saying "Arthur takes care of all of my light work." That incident occurs on page two hundred and eleven. 
His actual death is reported as happening on Monday, November 27th. 

"Luis Cruz is dead. When I walked into first period this morning, there was a group of kids standing around and whispering. Henry D. came up to me and said, 'Did you hear what happened?'
'No.'
'Tino and Theresa were waiting outside yesterday for Luis to pick them up, but he never came. Theresa called home and told their father. He went out into the grove and found him lying there dead.'"