Well established Hibiscus is dropping leaves/is naked. What can I do?

Question

My mom’s 20+ y/o hibiscus bush looks like it is dying. Located in Pinellas County FL. Weather temps have been HOT (95-103F) and have had a lot of rain. Began looking poorly three weeks ago and garden center recommended copper for bugs and yellowing leaves – then leaves began to drop quickly. Arborist visited a week ago and said maybe getting too much water and saw some eggs on a leaf. Mom put a small amount of fertilizer near base on the ground.
A new neighbor moved in a month ago and brought in a few plants/trees (maybe they had some disease?). Mom (90 y/o) is distraught over this. What can I recommend? Is it possible bush is dying of old age?

Answer 1

My first thought was advanced age. Hardy hibiscus is a long-lived plant, and 20 years seems to fit that bill.
Here is general care info:
https://www.gardeningknowhow.com/ornamental/flowers/hibiscus/outdoor-hibiscus-care.htm