Hi Rosie
I really hope that your contact to this forum has introduced some helpful early ideas and leads to follow up.
Please do keep us informed how you progress, We will of course continue to explore
all possibilities in resolving challenges.
Our prayers are with you and the family for a positive outcome.

You mentioned you still need advice on how to get the family to UK?
I would highly recommend you follow up on the suggestion of RickyR and make contact to an immigration specialist ( in addition to squeezing as much help as you can from the British Embassy in Manila)

This forum does have 'sticky' concerning an Immigration Solicitor.
Here are the contact details given:-

Mr Colin Harris of Harris and Co.
Soveriegn House,
1 Albert Place
Ballards Lane
(Near Finchley Central Station London)
LONDON N3
0208 349 8110
It seems Colin Harris can also be contacted on 07904 143686

For all sorts of technical reasons the situation of your brother, and importantly the immigration status of his family, are complex.
In my opinion it is essential to talk directly with a specialist who can give you an overview on a strategy for best outcome.

May I also suggest contact to the Foreign and Commonwealth Office here in UK
They are also able to offer specialist advice British nationals abroad seeking
help and assistance in emergencies.
It might seem yet another duplicated contact, but I'm sure it's a good source.