Wilting Amur cherry

Our neighbour has a lovely Amur cherry, about 10 m tall. In the last week, the leaves on about 1/3 of the crown have started to wilt. I checked for frass at the base of the tree and around the affected branches but only saw one spot that could have been there for a while. The leaves are rolling but there does not appear to be any insects on them. I am looking for any suggestions for the cause and if something should be done now.

 

Sorry but impossible to tell using only this picture and description

 

@Homewood, good afternoon, have you enquired how old the tree is ?
These trees have a life span of around 30 years. At 10m tall I would say it may well be nearing the end of it's time.
Agree with Ron that more photos needed, but thought you could ask whilst taking more.

 

The spots all over the leaves don't look good that's for sure

 

@GreenLarry, agreed but I cant see clearly enough for Cherry leaf spot.