Is there a Maggie's centre at the hospital which is treating your husband? Or indeed at any nearby hospital?
Staff there will offer you excellent advice and support, and will have s dedicated CAB officer who can help with finances, employment, benefits etc.
Has your husband applied for PiP? Sounds like he could apply under the special rules which means it would be fast tracked. You need your oncologist to sign a form if applying that way. Otherwise can apply under normal route if they aren't able to sign to say he meets the 12 month criteria.
If you have any debts or a mortgage contact your provider. They will pause interest, or payments altogether, or in the case of mortgages move to interest only.
Does your husband have a specialist nursing team he or you can call 24 hours a day bypassing A&E or gp if needed?
If you are in a union involve them in case of need, and take whatever is the maximum sick leave you can.
Your responsibility is family and yourself.
Bugger work.
I am a retired nurse and have stage 4 cancer myself.
Everybody is different but my cancer (melanoma but multiple secondaries in both lungs) moved to stage 4 six years ago.
Goes without saying I am so sorry for you both.
Ignore the abrupt and frankly weird first response.
Do whatever you need and stuff everything else.
Feel free to pm me if I can be of any support.