"I...." Sirius had to take a moment to wrap his head around this. On probation? "Look, I thought we had agreed to try this 'brothers' thing. We can't do that if you're avoiding me, or ... or censoring what you say to me, or making it for show.
"I can't promise I'll be around if you call -- I can be gone for days at a time, for work -- but I do promise that I won't refuse you if I'm there, and if I'm not, you could do far worse than my housemates -- hardly better than Harry, if you need protection, or Gaius, if you need comfort."
He reached out again, more cautiously this time, setting a hand on his brother's arm. "Despite our ... history -- or maybe even more because of it -- I appreciate having you as a friend -- as my brother. I think you have more than adequately proved your sincerity, and if you think I'm spending our every encounter judging you, you need to let it go. If there's one thing I've learned in the last few years, it's to pay attention to now.
He took a quick breath. "I never thanked you, by the way -- for keeping an eye on me when everyone thought Harry was dead." His grip tightened a moment, then let up. "I knew you thought I was mad, but you were decent about it, and it was comforting to have you visit."