Define Godbrother

While talking about weddings with Kugali, I found out that "godbrother" is technically not a word in any dictionary, at least according to my cursory research. How am I supposed to refer to Mike G, since he is distantly related but I consider him more than a distant relative?

Godbrother (noun) - son of one's godparents

Since Mike's parents are my godparents, he is now my godbrother. Godday to you sir.