My wife's finger nails are cracking and growing unevenly. Is this an indication of something serious? What should she do? She has added jello to her diet, but the nails are not better.

Your. Your wife may be dealing with a fungal infection of her nails (onychomycosis). There are over the counter treatments. See your local pharmacist for help finding the correct one. If that does not work she should see her primary care provider for evaluation and treatment as deemed necessary. A nail culture may also be necessary. Best of luck.
Have them evaluated. Some causes of abnormal nail growth include trauma, infection, side effects of medication, and possible systemic diseases such as psoriasis. Have them inspected by a professional to determine the cause of the problem, as treatment varies depending on the diagnosis.