Javier is the grandfather of Isabel. Isabel's cousin, Alejandra, often babysits for Isabel's younger brother, Carlos. Miguel is Alejandra's father. How is Miguel related to Javier, and does Miguel have a seniority-based familial authority over Javier?

Respond very briefly.
Miguel is Alejandra's father, and Alejandra is the cousin of Isabel. This means that Miguel is either the brother or brother-in-law of one of Isabel's parents. Since Isabel is the granddaughter of Javier, Miguel is the son or son-in-law of Javier. The familial hierarchy would therefore place Javier, as the grandfather, on a higher generational level than Miguel.

Since Javier is from an older generation than Miguel, he would typically be considered to have seniority-based familial authority over Miguel, as Miguel is either Javier's son or son-in-law. In most familial structures, the older generation (in this case, the grandfather, Javier) would hold a seniority position over the younger generation (in this case, the father, Miguel). Thus, Javier would have the seniority-based familial authority over Miguel, not the other way around.