Why not just encourage her to buy a set of All Weather year round tires, with mountain and snowflake stamp. Not going to be cheap but rated for 55,000 miles and you don't have to deal with swapping/storing them. Nokian WRG4 come in that size $160 each. Ebays about as cheap as I've found them. LLR also.
Toyo Celsius are available is that size but rated 60,000 miles. $135 each, don't think they claim LLR and one comparison between the 2 said Celsius was louder. Nokian being on the 4th generation of the tire have been doing it longer.
http://www.tractionnews.com/toyo-nok...-weather-test/
https://www.consumerreports.org/tire...ll-year-round/
If the old ones are any good sell those for her to help cover the cost.