If she wishes to stay with Yahoo! Mail, then perhaps open a new account (with them) utilizing a different account name along with a new password = (?).

Passwords should be complex and random. Not words that can be easily guessed. What I do is:
1. Minimum of 16 characters
2. Upper case, lower case, numbers and special characters mixed
3. Change passwords at least once a year.

Here's an example: #7BridgeClosedDetourAhead

It may or may not be good enough, but this password is not truly random.

And thank you; plus you are absolutely correct (!).

of the song.

From my childhood ...

Jingle bells, Batman smells, Robin laid an egg.

password: JbBsRlae

Then add some stuff that's meaningful. Perhaps your birth month at the beginning and date at the end.

password: 09JbBsRlae11

The hacker algorithms will never guess this. But, you can remember it.

Good luck and safe internet travels.

That works - and would be easy to recall.

Fyi most of the reports of email being hacked are not really true, spammers routinely fake the "From" address in email messages making it look like they've gotten control of your email account.

If the only evidence for the account having been hacked is email that was sent "from" their email account, before believing the worst, you need to examine one of the messages "raw headers" and check the "Received" lines and "Message-ID" lines and take a very close look at the "From" and "Sender" lines and see if the message was actually sent from a Yahoo computer.

I get messages every day from spammers pretending to have sent from my email account. So far, they've actually all come from machines outside the US or malware-infected systems being used as spam-bots.

Of course, changing passwords on yahoo and running malware scans on whatever computers they're using is never a bad idea.

Edit to add: unfortunately reviewing and understanding the "raw" and normally hidden email headers is a bit of an art form. When you first encounter them they can seem a bit complex. It's best to get some help as needed to figure it out.

However, changing passwords doesn't hurt anything.

Can also add 2-factor authentication (those codes that get sent to your phone).

Perhaps Try:
Wiki Recover Compromised Yahoo! Mail Account

Or Perhaps Try:
Recognize Hacked Yahoo! Mail Account