Who is Yndio in The House of Broken Angels?

The House of Broken Angels, by Luis Alberto Urrea (published in 2018), is a novel about a Mexican American family with many ties and a rich multicultural history that brings together their origins in Mexico with their American lives in San Diego. The protagonist is Big Angel (Miguel) De La Cruz, a terminally ill man of 70 who wants to truly celebrate life on what he knows will be his last birthday party. He is married to Perla, and the couple still love each other deeply. Their children are Lalo and Minnie.
Perla, Big Angel’s wife, has two sons from a previous relationship, Braulio and Yndio. Yndio is somewhat alienated from the family, as he does not attend the funeral of Big Angel’s mother, Mama America, which takes place the day before the birthday party. We learn from a family anecdote that Yndio once dressed as Cher at a drag nightclub, shocking one of the relatives in attendance. Yndio is not close to his stepfather, Big Angel.
When a gunman comes to the house with plans to kill Lalo, Big Angel’s and Perla’s son, his half-brother Yndio disarms him. This brave act brings Yndio closer to his stepfather. He accepts Big Angel as a father, a wonderful event that helps bring a positive closure to Big Angel’s life.