OK, I know your post came earlier in the week, just spending all weekend catching up.
First, if the money was in some kind of retirement plan at work, you will need to do a ROLLOVER so there is no tax consequence and the money can keep growing tax-deferred.
Second, you are at the stage where presumably you don’t want a lot of risk.
So go to Vanguard.com or call them and ask THEM to handle a direct rollover. Tell them you want to put it all into their U.S. government securities money market mutual fund. keep it there for a while. You won’t earn anything on the money, but you won’t lose a penny!
Then when that’s done, it’s time to think about risk/reward. You can write back then.
PS It just occurred to me that if she is in her mid-70s and has a retirement account, she should have been taking RMDs out of it in previous years (although none will be required for 2020). So are you sure it’s a “retirement” account and not just a wage deferral account? Ask the employer about that — and your accountant about the tax consequences, because this type of account likely cannot be rolled over.