A missed opportunity from the show, to be honest, not to have the reason that Suleiman believes Mehmed to be destined to take the throne after him (and, therefore, to invest heavily in his upbringing) to be the result of him assuming that only a truly "blessed" child could survive a poisoning and be born without any side effects from it.
I love this idea, and it makes sense from Suleiman’s perspective that he would assume that Allah saved Mehmed for a reason. Maybe the unborn Mehmed even gets some of the credit for Hürrem going from Death’s door to perfectly fine overnight, in the sense that he shared his blessing and/or strength with his mother.
The series missed an opportunity to showcase Mehmed as Suleiman’s favoured heir in Season 2B.
Mustafa was away for three years, with Suleiman apparently never visiting him at Edirne. Imagine if, after his return, he saw Suleiman spending a lot of time with Mehmed, training with him, talking to him about how to be Padishah, letting him watch Divan meetings, etc. Episode 55 could then leave him feeling torn, as he knows that his path to the throne will be a lot smoother if he’s the only adult Şehzade when Suleiman dies but, at the same time, he loves his father and siblings, and wants them to live.
It really is why I so continually feel like the show wasted a good deal of narrative potential through so continually defaulting to "aww no 🥰 they all love one another 🥰 forget about the fratricide law until we want to use it 🥰" (and the heavy Mustafa bias didn't help).
There's so much complexity to dive into when it comes to how the system of the Ottoman Empire called for what were normal familial bonds or human emotions to be set aside and eroded down. And it could be particularly wild for Mustafa since he was, quite possibly, shown Mehmed after the deaths of his other siblings in 1521 and told, "Here is a life you can still treasure," despite every adult involved knowing he'd have to one day kill that brother if he wanted to ascend to the sultanate.
