Yes. Sirus loved Harry because he was very similar to James (and sort of Lily) so he was like a reminder or shadow of the friends he lost. He also felt obligation and love as his godfather. Harry loved Sirius because he was the closest thing to a father figure (or at least uncle) he had. They were similar and he could confide in and solve problems with him, him being one of the few trusting close adults in his life.