It’s a crappy situation to be in and I have the fullest sympathy and empathy for you.
whilst I’ve never had cancer myself, I’ve known many that have. Sometimes the greatest source of information and “what to do next” without going down the expensive route is to get in touch with a charity that deals specifically with your brain tumour (if you’ve had an exact diagnosis). They’ve all been through what you and your family are going through now and are an absolute wealth of information support and will be able to point you in the right direction for treatment and care. And they’re a support network for the crappy days that you’ll inevitably have.