Can you imagine how different Sirius’ life would have turned out had he been offered an actual trial instead of being carted off to Azkaban?
They could have looked into his memories and seen that he was not the Potter’s secret keeper, that he and James had deliberately chosen for him not to be because it was the more obvious choice.
The Wizengamot could have realized within a matter of minutes that Peter Pettigrew was wizard responsible and that they had the wrong man.
The downside, of course, would be that said Wizengamot would also realize that both he and Pettigrew were illegal Animagi. Sirius would have to face the repercussions of this, which according to wizarding law means time spent in Azkaban (although one would assume this wasn’t a life sentence). However, the need to avenge his brother would outweigh that by far.
Following his release Sirius could have fought for custody of his godson. Or, at the very least, have visitation rights. I assume that James and Lily were smart enough to write up will during their time in hiding to ensure the protection and security of their child. Which meant that Sirius would have been guardian in the event of their death.
Although the sting would no doubt still be there, Remus wouldn’t be alone in his mourning. And with time the wounds and burdens of the war could ease. There would finally be honesty between them and the realization that Peter had deliberately turned them against each other.
So much could have been different, could have been better.
Dammit, I’ve made myself sad again.