IANAL but it surprises me too. Sounds more like 2nd degree murder. Lack of intention, lack of planing, lack of maliciousness.
https://manshoorylaw.com/blog/difference-between-1st-2nd-and...
https://manshoorylaw.com/blog/difference-between-1st-2nd-and...
It seems they have portrayed him as a cold, calculating murderer.
Second degree murder implies at minimum extreme indifference to human life if not intent to harm whereas he took her to the doctor then the hospital and gave her medicine then deemed medically appropriate and only now known to be harmful.
Where are you seeing the extreme indifference to human life?