I gather this is from Colins' book,nugs ?
I've a good idea why the boys were frightened. June and her Bible probably worked overtime. Poor little chaps were probably ruled with a rod of iron there,,and there could have been a certain amount of jealousy with June not being able to bear children as well,,.so it would have been a strained atmosphere at times.
If Junes' health was still fragile,,she wouldn't have been too patient with two boisterous boys in the house,,her not having been used to having youngsters around very often.Even Sheila and Jeremy would have learned from an early age that they do as they're told and speak when they're spoken to.