Basically, my MC's boyfriend left him with no notice, also leaving his two daughters aged around 8 and 16, possibly slightly younger, behind. The younger of the two was already calling my MC "daddy" at that point, and after certain traumatic events that proved to her that MC was more than "father's fucktoy", the older daugher also referrs to MC as her dad. These traumatic events have stirred up some trouble, and among other things the younger of the two children needs medical attention (she's starting to show signs of withdrawing into herself and becoming completely apathetic). Which is a pain to get when MC isn't a legal guardian for the child. Since the children's father introduced my MC as his boyfriend shortly after they moved in together and the kids moved in with them, this hasn't been an issue with parent/teacher conferences etc. before.
Neither of the kids' parents want custody of them, previous custody battles have more or less been trying to get the other partner to take custody. The parents are probably still married but haven't lived together in several years.
Would it be feasible for my MC to relatively easily get to adopt the children, considering the parents are willing to sign over any legal rights to them if it means the kids are no longer a hurdle in their love lives? To me this should be relatively similar to a pre-arranged baby adoption, but I couldn't find whether there was an age limit on these.
Does the fact that MC is around 24 years of age change this substansially?
The older of the two daughters is willing to testify that MC has gone above and beyond what can be expected of him, and that her little sister adores him. She'd ask her English teacher to help her write a speech if she felt it'd help. I can make this as long and dirty as I want to, and I can use tabloid newspapers to swing the public opinion in my MC's favor if I need to. The two children don't have any other relatives, so it's a matter of either the parents or the foster system if the MC doesn't get custody.
If he'd need to have a homestudy done (I'm assuming he does, but the kids HAVE been living there for maybe a year), I can probably research that on my own, and he lives in a rather posh neighborhood, so I'm assuming he shouldn't have much trouble passing one with a bit of preparation. If it's any difference, I can get him a fairly reputable and skilled lawyer through some contacts a friend of his has.