So sorry to hear of this Rubyx.. I think its one of the things Foster Carers are most worried about.
We attended an Allegations Course and some of the stories were truly horrendous.
I agree with scarlet - not to take it personally, and to record, record and record more.
Obviously they are duty bound to investigate, but it sounds like they aren't taking the things seriously... mum is obviously feeling threatened and you are an easy target.
I do think it is very good advice not to talk to him about it.. it is so easy to ask the wrong type of questions, that it could be seen as leading them..
He must be very 'torn' by this - hence not supporting nor denying it.. he's stuck in the middle, poor lad..
I hope your SSW is supporting you well over this - I know in some cases they have to distance themselves, but this sounds like a minor gripe on her part..
I find it bizarre that the mother perhaps thinks you should have celebrated a 'festival' as a family and excluded him!
Easier said than done, but try and brush it off as a desperate attempt to cause problems, not a personal attack on you or your family.
Best wishes
x x