No,"good-bye my brother" is just a saying.Nava and Aniu are not related.They just look alike.

I thought she was his mom because Nava said to Balto
"good-bye MY BROTHER". I wasnt sure if it was in spiritul
terms, or they really are brothers.

A lot of people think so, because they seem to look similar.
But I doubt it, and, like Fire_Paw said, this can also be
something the fans decide on. But if he was related to Aniu,
I'd think he would know Balto, am I right?

Plus, a lot of wolves resemble eachother. This doesn't
mean that they're related to eachother, only that they look
very similar.

It is possible that Nava and Anui are related.

No. What fire_paw said.

I doubt it. Though they kinda of resemble each other. It's
one of those unanswered questions. The is not ceratin they
are, but this is one of the thing that the fans themselfs
may decide on. I myself don't think it was intended.