Brokenwood idea that's maybe mildly darker than it needs to be:
Each of the Oadlings within the semi-au having a scar from something Bobby did (or ties back to his actions or inactions), with most of them being something that can be at least mostly hidden
(In no particular order):
Ladybird's is the most obvious having it on her face with the scarring causing mild paralysis on that side of it (pushed and fell onto a glass coffee table)
Rhys almost canonically has had multiple TBIs, but perhaps one of the more severe ones left a visible reminder that's hidden under his fluff of hair. Canonically the tbi incidents occurred from a badminton racket, a trampoline accident, and possibly him getting dropped, so Bobby's incident could either be the dropping or a 4th separate incident
Errol's would be a more indirect version, sporting either small circular scars on his temples or old self-injury scars, either way a result of his time at an early-days Deschler Clinic (the expenses were too high to keep him in the program, but the family accepted a partial refund in exchange for not publicizing how severely detrimental the "treatments" had been on him)
Ptyir's also aren't Bobby's technical fault, perhaps he'd have still have found himself working on the docks and on the boats too young for safety with or without some child support to pad the household expenses, but regardless there are friction burns set deep into the skin of his hands on both sides in mirrored set
Johnny's is well covered, a good hearted tattoo artist took special care in the design, opting for the scales of justice as a semi-subtle disdain for Bobby's ability to avoid real consequences (Johnny just agreed because he thought the design was badass)
Frodo. Frodo is a kind soul and a terrible liar. He was holding the gun when it went off, technically he did shoot himself in the foot. On the trip that Bobby slapdashedly organized. Everything that could go wrong did of course. They'd all seen what their uncle-dad could do when he was well and truly angry, it became a march on eggshells by the time they headed home. He rounded on Frodo for some inevitable infraction. The safety was off. It may not be a lie, but it doesn't tell the truth. He shot himself in the foot.
(I haven't come up with ideas for the remaining Oadlings yet, I'm still kinda workshoping the idea lol)