Hi Rosie,

I'm sorry to hear of your situation, it sounds very complex. What would you like to do with your brother and what sort of immigration information would you like.
If the child has been officially registered on the Philippines Birth Certificate as the son of your brother, then it should be very easy to arrange him for a visa. As for the mother, I think that would be something a little more complicated, and may need specialist immigration advice as it may be something under the Human Rights act.
Your brother will need to keep up his visa extensions in the Philippines, if someone is able to do that for him, that'll keep away some of the hassle.
There is a foreign assistance centre, which whilst not directly setup to help people in your situation, I would still contact to see if they can help. http://www.foreign-assistance-center.com/

Do you know what they are diagnosing your brother with, and whether it's worth checking his files with a UK NHS doctor to see what they think, and offer some input.

Does you brothers work not have a duty of care to provide travel insurance to him, I believe they may be liable for certain costs such as repatriation and this should be worth looking into.. As for the other repatriation options, some airlines are setup to receive stretchers and doctor, by strapping the stretcher on top of some seats. I have seen this before, and is much cheaper then a dedicated air ambulance.
I will be in Makati on the 28th September, if you'd like any help or for your brother to see a white face, then I don't mind dropping by.