We're generally advised to start telling anything that isn't fluffy bunnies by about school starting age, and to have told it ALL in age appropriate ways before puberty (though some suggest that anything along the lines of difficult origins - rape, incest, sex work etc. is kept for a little bit later but hinted at e.g. on one course I went on it was suggested in such circumstances you should be telling the child that e.g. their birth father hurt their birth mother, or that their birth mother wasn't sure who was their birth father, and leave the exact circumstances till a bit later).
So in Ryan's case they should have been telling him from very early on that his mother died after he was born and it was because she was very ill (depression being an illness) and sometimes mums get very ill after babies are born (postnatal depression being very common) and then later adding in that they get so sad they don't realise how much their babies will miss them when they are gone. And they should have been telling him both what his uncle said about them not really being boyfriend and girlfriend, and about TLR pretending he liked Ryan's mum, and then adding in that TLR hurt his mum both by being mean to her and pretending he liked her, and also that he hurt her physically.
And he is now of an age where they can say that sometimes men hurt women by forcing them to have sex, and that's how TLR hurt his mum, and that his mum was just so so sad after all this happened, and she got so sick that she couldn't see how to take care of Ryan, so she killed herself but she knew that Catherine and Claire and Ryan's uncle would take such good care of him.
We are also usually advised to say that some of the things that people do to hurt others are because they were hurt themselves as a child, and that none of this is the child's fault, that they should be taken care of by adults, it's not up to them to take care of adults. Even when thinking back to themselves as babies, some children think if they were a "better" baby their parents would have stuck around etc.
(Sorry for the lesson...)