I think their father was the best judge of that and he thought otherwise. He was probably further guided by Dr F who he claims told him SC would always suffer the condition and with increasing regularity. If medication is the panacea you seem to think it is why didn't he say 'Oh she'll be fine if she takes her meds'?
You think he's the best judge 'on this occasion'? At the time the twins were with him, Sheila wasn't able to look after them obviously and he did the right thing in taking full care. However, given that his word is now reliable, where in Colin's words does he mention it being a permanent arrangement?
Millions of schizophrenics live their lives with their children having been stabilised on medication. I'm STILL waiting for you to provide an example of someone killing in whilst in the midst of a psychotic episode while regularly taking their medication. The last example you provided, the individual had admitted to having not taken.
I can't answer why someone didn't say something but I suspect he was taking things one step at a time. Perhaps he even. did mention it, but Colin had no faith in the conventual meds.