I purchased a Gensing Grafted Ficus tree that is 6 years old from Amazon (through Brussel’s Bonsai). The Amazon delivery guy left it on the front porch when we were out of town for a couple of days. It was exposed to temperatures below 40°. I believe it was 17° so it’s been a month and it’s lost most of its leaves. I just noticed that it has some white fungus growing on the bark. See the attached pictures. I purchased some organic Bonsai food and gave it a little bit in the soil area. I also have watered and spritzed the limds to moisten them 2 times per week since it was delivered. I have it in a very sunny location. Should I expect this tree to come back or will it die?