A few thoughts about guide books. While I usually find the RS guides to be really helpful, the guide book on Ireland is particularly spotty in what it covers. Consequently, if you use it, I would supplement it with at least one other guidebook. I found Frommer's guide book to short sightseeing drives to be amazingly helpful in finding what's along the way as you drive; I don't remember the exact name, but Google it, it's easy to find. If your mother is Interested in history, art, or architecture, the blue guide is the best source you can possibly use.
Also, I assume there's a reason your mother wants to go to Ireland. How about getting one of the photo based guides – like the DK Eyewitness guide – and spending some time with your mother and that guidebook. She probably knows what types of things she wants to visit.
I have not traveled there in February, but Ireland tends to be wet and chilly even in the late spring and early fall – the times I've been there. So planning a fair number indoor activities would be a good idea. Scenic drives are also a good option, provided it's not too foggy or raining too hard. Things like Muckross House or maybe even one of the banquets in a castle occur to me. But if you do visit one of the castles , make sure your mother will be able to Handle the stairs. Daylight will be short at that time of year, so after dark plans will be important. Also, off season, tourist attractions in some rural areas are likely to be shut down.
To return to your original question – the paid advisers at RS – I've used them twice. One time the person was well prepared and it was very, very helpful. The next time the suggestions were broad, the person didn't seem very prepared, and it was much less helpful. However, it occurs to me that $75 isn't much compared with the cost of your entire trip, and since you're going at a less than optimal time (regarding weather and daylight hours), with an elderly parent, some expert advice might be good. If you plan drives out of the major cities on day trips, I would particularly want guidance on what Will be closed for the season.
A couple of other thoughts. Once you get off the main highways, driving in Ireland will take a lot longer than you expect, so don't try to pack too much into a day. Also, based on my experience traveling with my mother when she was that age, doing fewer activities allowed her to enjoy them more.
Have a wonderful trip!