I would suggest the first thing you do if gather immediate family and friends together and say that you need to raise funds. Then setup a crowd funding project, tell the story and spread it through facebook as much as you can and brainstorm together about ways you can raise money. Notify local newspaper and tv news and radio and try and get their help. This is something your brother may or may not want to be involved in as it can be very stressful and time consuming in an already very stressful environment.
We did raffles (but prizes were donated from businesses in the community), a monster garage sale where everyone donated things they didn't need from their house and we turned it into a family fun day in a park with jumping castles and balloons and food etc, people sold things on eBay and gave us the money, donation tins in the shops in the area, the schools had a special dress up day where they came dressed up and paid a donation towards the charity, we had pizza shops donating $1 from every pizza for a week.
It is all very overwhelming now I am sure, but if you all work as a team I am sure you will get there
