To your remark about Melissa coming too late, even 6 years can be too much. I know families where the first child is much (~5 years) older than all the others and it can create a really unhealthy dynamic - the kid is used to being the only child, he's old enough to remember being the center of attention, and he's old enough to understand the new baby is taking away "his" attention but not old enough to understand babies need more care. Melissa might be older than Phil but she wasn't in his immediate family until he was about 6 and she probably needed more attention due to her extremely dysfunctional parents so it could have happened with her and Phil even though she is older. Given how Phil reacts now I could totally see his parents just buying him new toys to shut him the fuck up while they tried to figure out to what to do with Melissa.