Oh dear Alicia, my heart hurts for the pain & guilt you are feeling, so sad!
I have no experience w/this but others here do and will advise you.
Know I will begin praying for you and precious Otto, that he begins recovering
immediately and without complications.
Please be kind to your self, we are not the experts and so, can only do as they
advise what is best for our bullies. Sending hugs of comfort & strength...