Do we think Grant heard Enough for you by Olivia Rodrigo then immediately broke down because he could be the greatest boyfriend, friend, husband, or roommate, but he could never be Sirius. In the end Remus would always leave him because he's not Sirius.
Or maybe he heard Less and remembered that day Remus told him he couldn't keep hurting him because he was always going to be inlove with Sirius.
Perhaps he heard Cigarette smoke and remembered that first summer where they would sneak around and kiss and he could taste the cigarettes on Remus breath after they shared a smoke wishing more than anything that even after all this time together he could finally just love him more than he ever loved sirius.
Or Logical came on the radio and he had to pull over because the only thing he could think is all the times he was referred to by "Sirius" or "Padfoot"
anyways go stream Olivia Rodrigo 😋