Disabled Living Allowance/Attendance Allowance should be claimed now by your father or if he is unable by your Mum ring 0800 88 22 00 this a benefit enquiry line who will be able to issue the forms and give you any advice, this is you fathers right and is not based on means, it is also non-taxable.
As Ethel says 25% reduction in council tax, must be applied for. The rest depends on circumstances, like private pensions etc.
Do take all the help offered especially from the medical services, don't let your Mum do too much herself as she will try to do.