It's no longer the end of the world and your car has broken down, which of the Scions of the Seventh Dawn do I think are most likely to get you out of this pickle, let's go. (Endwalker tier list)
Honorable Mention (Not a scion): Uually Cid sits on the throne here, but for once he's out of his depth. Even Airship Grandpa can't rescue us at the edge of the universe. Instead, I think there are two more canonical honorable mentions: Emet-Selch and Hythlodaeus. Would Emet be happy? Absolutely not. Would Hyth make him fix your car anyway? Give him ten minutes and a cute enough smile and he'll even make him give you an upgrade.
G'raha: Not only do I think G'raha to be a highly reasonable first choice, I am also morally obligated to call him first. Maybe it won't be an exciting adventure, but the light in his eyes when he realizes he gets to rescue you will keep you going for weeks. He gets really into it and manages to fix your car by the side of the road, then smacks himself later when he realizes that means he didn't get to drive you home.
Tataru: Tataru has enough mechanics on speed dial now that she doesn't even have to come herself. In twenty minutes Biggs and Wedge are there toolbox in hand. There is no shred of affection this woman will hesitate to use. You call Krile to discuss these events as soon as they leave.
Estinien: Oh how the mighty fall and new warriors rise. Estinien is officially a Scion now and he's even worked through his anger issues. If you call Estinien at any time of day or night he will happily drop whatever responsibility has gotten it's grasp on him and immediately race to you. His new car has every bell and whistle on it imaginable and a 28% interest rate. It is an extremely comfortable ride and he offers to take you back to your car when you can get it towed. Do not allow him to talk to a single mechanic or the tow truck driver and you're fine.
Krile: "You called all three of them? And nobody answered? Do you think G'raha fell asleep standing up again? That's the only reason he wouldn't answer your calls. Actually I'm going to go check on him after I drop you off, have to make sure he's not dead. I'm joking, I'm joking! Though I am a little legitimately worried. Did you know that Tataru has been taking calls from Hancock of all people lately? She acts mean but personally I think she has a bit of a soft spot for him. It's very rare to find someone almost as ruthless as her, and I think he's quite excited to have met his match. Estinien? Oh I know where he is, you're never going to believe this-" A+ no notes.
Thancred: You call Thancred and he arrives with Urianger in tow. It's two in the morning. Thancred drives and Urianger navigates. You are given updates on each of the loporrits, some of which you don't ever remember hearing their names before. Urianger keeps turning to Thancred and smiling. After they drop you off you start texting Krile to give her an emergency update as soon as she gets up.
Urianger: You call Urianger and he arrives with Thancred in tow. It's three in the morning. Urianger drives and Thancred navigates. Thancred wonders why G'raha didn't answer the phone first and questions whether someone should check on him. Urianger has his hand on Thancred's thigh and neither one of them seems to notice. After they drop you off you start texting Krile frantically to give her an emergency update as soon as she wakes up.
Y'shtola: She is please you waited until almost last to call her so that she can once again hold it over her colleague's heads. She talks theory with you the whole way home as you spitball ideas for traveling across the worlds. At one point she stumbles a bit when talking about returning to the first to visit Ru- Ryne of course, yes, Ryne. You pat her head on the way out and run before she can throw a fireball at you.
Alisaie: With an entire gaggle of somewhat responsible adults available you did not think you would need to rely on the teenagers this time, but here you are. Alisaie will pull up in her new shiny red car from her mom. She's excited to be able to do something for you for once. She does wonder if G'raha's ok though.
Alphinaud: He shows up in his new shiny blue car from his mom. He says something along the lines of "Just the two of us again, friend" and waxes nostalgic about your time in Ishgard. He wonders if Estinien is ok since he didn't answer the phone. You suggest he ask Krile tomorrow.
Bonus: You find G'raha asleep on your front porch steps. In his flurry of information gathering he didn't sleep last night. When he leaves the library to go home he realizes he's locked his keys in his car. He decides to call for help only to see his phone next to his keys. While trying to figure out how to bust a window without completely destroying the car, you start calling him. He can't answer and can't call you back, but is not about to abandon you if you need help or lose out on any of the fantasies his mind is concocting, so he begins walking to your home. By the time he arrives he's exhausted and when you don't answer he falls asleep waiting for you. Any of the Scions who drop you off nod sagely when they see him there.