They'll leave her with £14000. Once her capital is down to £23000, the Council will start contributing. When she's down to £14000, the Council will pay the fees in full. She'll still have to pay for "extras" (like toothpaste, hairdressing, someone to cut her toenails) so that will whittle away at the £14000 if it can't be accommodated within her pension.
While she's completely self-funding, she'll be able to apply for Attendance Allowance (if you can get that as well as DLA, you may not be able to). While she's completely self funding she'll still get DLA, but that will stop once the Council is contributing.
Should she not be getting Pension Credit on such a low income?
The thing you need to be careful of is "deprivation of assets" - if she does anything (eg put your name on the bungalow deeds so that it becomes half yours) that can be construed as divesting herself of assets to avoid paying for a care home, she will be treated as if she still had those assets. Local authorities are getting very aggressive about this, and delve back into the records a long way.
If you haven't yet done it, set up a Power of Attorney, so you and DB can manage her affairs if she becomes incapable.
It's a very unfair system. It looks fair, because people will say "why should the state pay if they've got money to pay themselves" "they can't live in the house so why shouldn't it be sold?" "Why should I as taxpayer fund other people's children's inheritances?" But it's completely arbitrary - your neighbour dies from a heart attack and his children inherit the house and all the savings, your other neighbour has been enjoying her "savings" during her lifetime and has her care paid for, and you are diagnosed with dementia and your children inherit nothing. And because there's no limit on care costs, you cannot insure in the way you would for, eg, your house burning down.
And it's not as if we don't pay for other people in other ways - eg tax relief on private pensions, so the more well off you are, the more the taxpayer is contributing to your pension.
There are some advantages to self paying - for example, she can move into assisted living accommodation when she wishes rather than when the Council thinks she needs is, so you don't have a long phase being run ragged while she doesn't quite cope in her own home with 4 half hour care visits a day.