Settled Status - when already have ILR

[NameChangedAgain18]

Can anyone help me decipher the government webpages for Settled Status?

On this page, it states that "you will not need to apply if you are an Irish citizen, or have indefinite leave to remain":
www.gov.uk/settled-status-eu-citizens-families

But then, the page on how to apply seems to suggest that you will need to apply if you have ILR, and that the fee will be waived:

www.gov.uk/settled-status-eu-citizens-families/applying-for-settled-status

I'm asking because my mother came here in 1965, so pre-EU. She has never taken British citizenship (which would, at the time, have meant giving up her French citizenship) but she has either permanent residence or ILR (I'm not sure which, without checking). Is this going to become void at the point of exit from the EU, requiring her to apply again for the rights she had already been granted? Is anyone else in a similar position, and can advise?

I am surprised that the French do that because they do not "own" the visa stamps in the passport that have been issued by other Governments.
But I guess all French people have identity cards.

Actually OP, it might be worth asking a US French Expats group because the US and France have had "issues" many times during the 80's and 90's
so visa transfer will be an issue