I recommend that your mother have an appointment with a low vision specialist. This will be someone other than a general ophthalmologist or general optometrist because the specialty requires additional training and expertise in the use of many different forms of magnifying aids and magnifying products that a general practitioner will not have the necessary training in or equipment and product samples to do a proper evaluation.
There are many, many, products available that range widely in price, size, weight, and method of use, be they portable or stationary products. The elderly often struggle with devices that they purchase if they are not informed and trained in advance about how to use them properly to gain the most out of them, and in many cases, two or more magnifiers or devices will be recommended to the patient based upon their specific needs and visual handicap.
If your mother is in the state that you have in your signature, you might look into nebraskamed.com/eye-care/low-vision which I found in a web search using the words low vision specialist, nebraska; but there are several others that come up when doing that web search. That particular site has useful background information regarding what low vision aids will do, which admittedly is frequently limited and may not completely satisfy your mother depending upon the severity of her eye problem. You may want to see if there are positive reviews of any of names or centers that you see that are hopefully convenient to your mother as more than one initial visit and follow up may be necessary. Make sure that whoever she decides to make an appointment with clearly specifies that their practice is largely in the area of low vision.