baby spiral fracture feel so bad

[AnyDream]

What a horrible situation. So sorry your little bubba has broken her leg, fortunately at this age it should heal up really quickly.

I have no doubt that whatever happened was an accident - in the sense of even if your nephew did something he wasn't supposed to (and knew he shouldn't) there is no way he could've anticipated that the outcome would be a broken leg, kwim? So I think the helpful strategy here is to try to shift away from blaming - accept that is HAS happened and you can't turn back time - and you can't peer into the room and find out exactly what happened either - and now start to think about what you need to do from here on in, kwim?

For starters, you are going to have to supervise your DD 100% whenever those children are there. Don't make a big deal about it but make sure your DH and any other adults are on the same page. This can be done discretely without being in your sister's face if you want to avoid conflict, or deliberately in her face so she realises there is a consensus of concern by other adults in your child's life (grandparents, mutual friends) if you choose to go that way.

I think the issue of concern is that this is part of a larger pattern of behaviour. Hard to say without knowing what he was doing in the previous incidents. Have you talked to her or her partner in the past about the things you have caught him doing? If not, leave it be for a bit and then have a conversation with her - not just about this latest incident - but about everything and why you are concerned about him. Wilfully causing hurt to small children and animals etc can be an early sign of sociopathic tendencies - I do so hope that's not the case here - but in any case it's a set of behaviours that he needs to learn is unacceptable. Esp if he is doing it to get his mother's attention, kwim?