Two good points.
Sheila would have wanted her whole family gone. But knew her brother, who did not like her or understand her illness, who she did not like & who was present during the alledged fostering conversation was not at WHF ?
With Neville & four of his immediate family in danger, why an earth also put his only son in danger ?
Adam,,show me a young man of 24 who's interested in his sister. Jeremy was enjoying working hard and also playing hard,so his interests,like any other young 24 year old,were taken up with going out and partying,,but at the same time,he saw Sheila when he was able and hadn't cast her aside.Both of them became closer as they got older.
Surely,Jeremys' alleged remarks about his family would have proved his lack of interest with his involvement in age and illness,so therefore,he wouldn't have studied any existing illnesses in any of them. ( This remark is on the back of what you posted about Jeremy knowing about the fostering situation .)
Pam knew about the fostering arrangements,who in turn would have told RWB,who had the brass-neck to deny that it was ever mentioned !
Both Sheila and Jeremy weren't strangers to being looked after by people other than their parents,while growing up.There were a number of different au-pairs in situ on account of Junes inability at times,,so for others to take turns in looking after the twins,wasn't a big deal,,although it was twisted into a criminal act when Jeremy happened to mention it.
Everything that man said was twisted beyond recognition.