People think that when multiple siblings enter the priesthood or religious life it has to do with the parents, or a younger sibling "coping" the older one. (I think the Little Flower ran into this belief). But our vocations are very mysterious and individual gifts. Often God "clusters" vocations to religious life and the priesthood in the same family for His own Holy Reasons.
I was happy, but not so surprised when Father Gary put this story on Facebook --three brothers from Wisconsin all joined the priesthood. Go Cheeseheads!