I’d like to think that after he died, Regulus was looking over Sirius.
And by looking over him, I mean that Regulus was constantly facepalming and yelling at his brother from the afterlife.
“I don’t care how many galleons James offered you - you cannot drink ten pints of Butterbeer and still have an intact liver! Well, great! Now you’re in St. Mungo’s for a week! Bloody idiot!”
“Sirius, don’t you dare levitate that police car, you - sodding idiot! Have you completely forgotten about the secrecy laws! And Elvendork’s a terrible name!”
“NO, SIRIUS, YOU ALREADY PUT FIVE DEER PUNS INTO YOUR BEST MAN SPEECH! YOU DON’T NEED ANOTHER ONE!”
“No, no, don’t make Peter your Secret Keeper! Anyone with eyes can see that he’s a Death Eater! Crap! Crap! CRAP!”
“Alright, look, I know that you’re grieving but you can’t JUST GO AFTER PETER! SIRIUS! STOP! DON’T! WELL WHAT EXACTLY DID YOU THINK YOU WERE GOING TO ACCOMPLISH FROM THIS!?”
“Alright, alright, alright, just explain everything to those Ministry officials! Contact every Order/Auror connection that you know and maybe you can-Sirius? Sirius, stop laughing. SIRIUS! SIRIUS, THIS IS NOT HELPING!”
“NO! Bad idea! Escaping from Azkaban is a very bad idea! You’re going to throw the whole world into a state of panic and - there you go…”
“Merlin’s balls, Sirius! ‘Only one will die tonight.’!? Stop being such a bleeding drama queen and just tell Harry why you’re really-oh look, now he’s pinning you to the ground! Who could have foreseen that!?”
“SIRIUS, LISTEN TO ME, YOU DO NOT WANT TO DUEL BELLATRIX! GET BACK TO GRIMMAULD PLACE BEFORE YOU…SON OF A BANSHEE!”