Q.red weeping maple has tiny dried up curly leaves
About 75% of my red weeping maple has only tiny dried up curly leaves on the branches. I have a 5 year old red weeping Japanese maple and this year only one section bloomed with healthy leaves. I just pulled off all the old mulch and some of the mulch has a white substance on the bottom of it. Someone suggested I gently scrape a couple of branches and if there is green below the bark they are not dead branches. I gently scraped and below the bark was only white or a cream color. 25% of the tree has healthy leaves and I just saw a new shoot of healthy leaf out from the trunk of the tree. Do you think this is a mulch fungus problem or something else could be the cause of the problem?

The white substance under your mulch is likely only the naturally decomposing material, but this article will give you additional information and ways to identify other types of mulch fungus:
https://www.gardeningknowhow.com/garden-how-to/mulch/common-mulch-fungus.htm
The dried up curly leaves "could" be something as simple as not enough water, but not likely. Verticillium wilt is common in Japanese maples but the leaves turn yellow before falling. The most likely cause of your maple suffering (based on the symptoms) is aphids. This article will help you positively identify and remove them: https://www.gardeningknowhow.com/plant-problems/pests/insects/aphids-tree-disease.htm
And this article may also help you: https://www.gardeningknowhow.com/ornamental/trees/japanese-maple/japanese-maple-problems.htm