If she puts the house in her children's names and lives in it, she will have to pay her children the full market rent. The tax people will check that each year and that it rises(or falls) in line with the market in her area. If she doesn't pay the rent, the house will be deemed to still be hers and it will have to be sold to pay fees.
It also depends when she does it. Do it at 50 when in really good health and you will get away with it, but you need to remember that if you give the house to the children it will form part of their assets and if they go bankrupt, or divorcr the value of the house will form part of their assets, so she might have to move out because it needs ot be sold, alternately, if at any time the children just decide they want the money they can give her notice to quit and sell it whether that is what she wants or not.
When worked for a charity I was sent ot visit on old man in his 90s who had given each of his children a share in the house and paid them rent, but in his 90s, which he had never expected to live into, and living in what was now a highly desirable and expensive area, the monthly rent exceeded his total monthly income.
I am afraid your friend really is being very naive if she thinks something as simple as this could get you out of paying care fees. If it worked, everyone would do it, which is why the government closed that loophole.
Has she given any thought to the quality of care she would get if she relied on state care? Nowadays, state care means your local council decides where you go and if you do not likewhere you are, well tough luck. Personally I would do anything to be able to fund any care I need myself and go into a care home of my choice.
Here is a useful link, but be aware it is a commercial site. ukcareguide.co.uk/avoiding-care-home-fees/