Hello, and thank you for your medical question on e Health Forum.
From the description it seems that your brother has suffered a severe stroke affecting large areas of the brain.
Symptoms and disability following a stroke vary greatly depending on factors such as the part of the brain affected, how quickly treatment was given, and the extent of the damage to the brain
Since the treating doctors have already done a craniotomy to relieve the pressure within the brain, it will take some time until the brain heals and then once the fluid collection in the brain reduces, your brother might improve and eventually gain consciousness.
You might work with the treating doctors and neurologists for proper care and continued support of your brother.
I hope this helps.