Alastor smirked and shook his head, declining the invitation to sit. He had a wall at his back. He was good.
"No, prying would be intending to do something about your intentions. Whatever is between the two of you or isn't, I don't need to know the details and don't have the patience or the talent to play agony aunt." Alastor giving relationship advice had been weird enough the night before. He didn't need to make a habit of it. "I do, however, need to know if I'm dealing with someone who can be a friend to my brother, someone just after a shag, or a man looking for something more."
Alastor may not want to interfere, but how much he trusted Charlie to help him look after Cal would depend on Charlie's answer. Cal didn't need help from unstable roots. If Alastor was going to convince him he had a solid thing here, that he didn't need to run away to 'find himself', he needed the assistance of people in it for the long term.