Looks like a classic case of "Fire Blight" to me. It usually affects apple trees but.... since apples decended from roses (closely related species) Fire Blight will affect roses from time to time.
It commonly affects pear trees too, another closely related species.
It's a disease caused by a bacterium (Erwinia amylovora) that thrives in the warm, humid, and rainy weather that coincides with the start of the growing season, and it is easily spread.
A pesticide is useless against bacteria, a waste of money that does nothing! Tell her to contact local rose or garden clubs, the county extension service... etc. They might can help some.
Even when treated properly it may kill all her roses anyway. It's a nasty, almost impossible to stop, disease. NOT a pest/insect.
@Meerkat I just noticed the sprinkler in the first photo... TURN IT OFF! Humidity and water causes the disease to spread faster!
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