Yeah, say whatever pretty speech you want, you still have no connection with this kid. Aside from bumping into him, hopefully remembering his name. And abandoning him like you abandoned an entire planet of living creatures to look for alien dirt. I'm inspired to spit!
Dylan is Brian's son, sure, but what does that really mean? It meant that Brian had a one-night stand with someone he didn't give a shit about and took advantage of, and abandoned all responsibility. Like this speech here, it would work, it'd make sense if Brian was the victim of parental alienation, or a harsh custody battle, or an accident, or lying, or hell, if Brian didn't intentionally use Dylan selfishly for his own ends and nothing else, without consideration of Dylan at all. Just because Brian is biologically related to Dylan doesn't mean jackshit in the end. It doesn't mean Brian is anymore prone to changing for Dylan. But because this is a story about parenthood, the child or teenager's ending means fuck-all, as long as the dipshit adult gets his happy ending.
Loretta: Listen. I always wanted to be enough for you boys. I think that's why it always hurt when you asked about your dads. Because I was always trying so hard to be both parents for you. But I was being selfish. You deserve the truth, so here it is. Sam is not your father. [...] But if you want, I can tell you who it really is. (pulls out piece of paper)
Barney: (rips up paper) It's okay, Mom. I don't need it.
Loretta: But it's your father.
Barney: I already have a father. And his name is "Loretta".
Barney: (rips up paper) It's okay, Mom. I don't need it.
Loretta: But it's your father.
Barney: I already have a father. And his name is "Loretta".
"I did a great job with Soph all by myself, and I won't be muscled out by an ejaculation."
— Donna Sheridan, Mamma Mia!
