The dividends and interest payments plus S.S. meet her needs at present and she is in good health.

Good. That give a lot more flexibility.

Are my worries unfounded?

Yep. Those are just general guidelnes, not specific recommendations for everybody. If the income is adequate and she's not tapping into the principal, you're fine. Any major adjustments will cause a loss of principal to income taxes.

However, those taxes need to be looked at in the bigger picture. Is she really paying much income tax right now? If not, taking some small capital gains to slowly reallocate her portfolio might make some sense.

Do I need to do anything?

Not necessarily. If she needs to start using up the principal of the accumulated funds, then you might want to reassess. The most likely user of funds would be medical expenses. And those are tax deductible when they get large enough. So that would be a time to start making sure that there is enough income recognized to use up the available deductions. IOW - that might be a time to start taking some capital gains.

Is this a job for a professional?

Not necessarily. They'll just take fees for advice no better (and probably worse) that what you'll get here.

--Peter