From Wiktionary, the free dictionary
From Middle English godbrother, equivalent to god- + brother.
godbrother (plural godbrothers)
- The son or godson of one's godparent, or the godson of one's parent.
2008, Sharon Cheston, Faded Rainbows: Psychospiritual Therapeutic Journeys, iUniverse, published 2008, →ISBN, page 29:I got excited at the prospect of even more fun in this wonderful house with my godbrothers.
2010, Wes Moore, The Other Wes Moore: One Name, Two Fates, Spiegel & Grau, published 2010, →ISBN, page 97:Wes and his godbrother, Red, moved toward the cheese bus as it slowly rolled to a stop in Dundee Village.
2013, J. W. Wiley, The Nigger in You: Challenging Dysfunctional Language, Engaging Leadership Moments, Stylus, published 2013, →ISBN, page 35:Her worldview may also be favorably tweaked by her having a godbrother with cerebral palsy.
2019, Hou ShenDaShu, The Happiness, Funstory, →ISBN:"My mom took him in as her godson, so of course he's my godbrother!" Jia Li said with a hint of pride in her voice. Old Shen, you are awesome!