That was the first Hermione had ever heard of her brother-in-law being the least bit interested in Antonin's activities. Following his arrest at the end of the first wizarding war, all three of Antonin's younger brothers saw him as a cautionary tale. None of them wanted to end up with their life ruined in Azkaban. When the Dark Lord finally won the blasted second wizarding war, they continued with their lives outside of the borders of their native country out of fear that they would be somehow pulled into the violence. They only returned for brief visits. Aubin never seemed to want to even be in the same room as his eldest brother for more than an hour or two at a time every five or six years. Knowing that he hoped to be of assistance when Antonin became the Dark Lord was a surprise indeed.