Destiny is Genre Savvy, possibly to the point of Medium Awareness.
She was attracted to Matthew in the first place because she knows that being a Buchanan's love interest is the road to becoming a main character.Since his accident, she's acted on the principle that spinal cord injuries in Soapland aren't quite the same as broken bones in Real Life- they require grabbing the first plot twist that can lead to a cure and hanging on tight- hence her encouragement of the risky surgery/sue his parents for the right to choose it scenario.If the writers get used to him being a paraplegic, the window of opportunity closes. And he can't die from the surgery, his actor just signed a new contract.- Whether she's doing it out of self-interest (she has a better chance of being her generation's main character if she's paired off with Matthew as The Generic Guy on foot than if he's The Woobie in a wheelchair), or out of a genuine desire to help is another matter.
- The writers are very fond of Teen Pregnancy storylines, but medical assistance is usually required for a paralyzed male to father a child, which would rule out a High School "accident".
- Prior to the accident that left Matthew (temporarily) paralyzed, there was an episode where Matthew confessed to Destiny that he'd killed Eddie Ford. Destiny realizes there were extenuating circumstances and is very supportive of Matthew. After they talk, we see Matthew holding Destiny's hand and leading Destiny upstairs (where his bedroom is.) It's later confirmed that they did, in fact, make love - it was the first time for both of them - and that is when Drew II was conceived.
- The writers are very fond of Teen Pregnancy storylines, but medical assistance is usually required for a paralyzed male to father a child, which would rule out a High School "accident".
Matthew, Bo and Nora are developing genre savvy.
That's why the only possible outcomes they can consider for the surgery are "I'm going to be completely cured yay!" and "ZOMG that butcher is going to kill our son!!!" In a Soap Opera, those are the only possible outcomes. "Limited improvement but still a noticeable disability" is the stuff of Real Life. Cole's withdrawal hallucinations were originally plotted to be an intervention.
Who is he hallucinating? Not the usual Mushroom Samba creatures, but his family and friends - exactly the people who would be there for an intervention. No more, and no less. The switchover probably happened in the writers' room while brainstorming, when everyone lost track of what the characters would say, and jumped headfirst into what they thought the characters should say. With all that material that Crosses the Line Twice, it became a matter of tweaking the outline so they could use it rather than adapting it to an intervention scenario. The producer and director didn't argue with the switch to hallucinations because it saved them the cost of hiring someone for a day to play a facilitator.