My guess is, Harley is going to be living with them full time. She said something about Harley not wanting the dinner they’re having. Why would he be there, as it’s term time? She described the “thing she can’t talk about” as sad and exciting. I may be wrong, but looking after your own child after a loss would be a challenge, but Harley is likely missing some maternal parenting (although I don’t think Abi is particularly maternal, she does seem to do a lot with Harley when he’s there) I don’t think Dan and Erin were together for years, and when you’ve not been a parent before, I can see how it would be difficult. At the time, they’d have wanted to agree with anything Erin asked, but grief, parenting and uncertainty may have meant Abi and Chris would be a better choice for him- he’ll still have the connection to Alex too. I know Abi said they aren’t really that close, due to their age, but again, loss and grief make you think differently