Sorry, a bit abrupt before. Yes, you have had a terrible time, so now take a breath - it is a bereavement, so take time to grieve too. If you have help and family around you, let them take up the burden a bit. Make an appointment with Citizens Advice too get expertise.
All benefits will not stop, they will go to his care placement once he has been permanently placed. The six weeks is a grace that you will continue to receive as his permanent home is still yours.
If you are alone and unemployed, you will need to apply for income support, and reduced council tax (you get a reduction just for being a sole occupant), and may get more if your income is low.
Check your state pension, because as a carer, you will have been entitled to NI contributions paid for you.
If HE has any work or private pensions, do contact them to see if his dementia may activate a payment, some do.