In the original Hogwarts Universe, Bastian took up Jonah's dream of being an Auror in order to be closer to him. It wasn't exactly a bad thing as he had no real drive of his own at the time and it caused him to be more focused on his studies.
At the academy he did well, not overly well, but good enough. However his cat Estrella died a day before the Auror finals started. Bastian was very attached to his cat and that messed him up, enough for him to fail the tests badly, even the disguise and concealment portion (a part he would have easily aced because he's a metamorphmagus), and question what he was going to do with his life afterwards.
Bastian starts traveling the world without Jonah because he realized in part why he took up being an Auror and that revelation made him think his attachment to Jonah might be unhealthy to them both.
....As it turned out, four-six months of traveling and soul searching(I cannot remember how long I had it) only told him that Jonah was the healthiest thing in his life and he returned and tried to act like nothing happened, though that long break clearly messed them both up.