Thanks for your question about your apple tree's problems.  You are correct in that this spring has been ideal for the growth of many types of fungi (cool and wet), and controlling it is difficult with larger trees.   In order for us to recommend a plan, we need to identify what your tree has, and, frankly, the photos are rather out of focus, and I'm having difficulty seeing them clearly.  

There seem to be brown spots, about the size of a dime, on some.  Others are almost completely brown; others have small irregularly shaped brown spots.   And the last photo seems to have quite a few dead leaves close to the branches.  But I can't tell if there are cankers on the branches as well. 

Any way you could take some leaves off the tree, and photograph them against a sheet of white paper?  Top and bottom of leaves would be preferred.  And, if you can get a better picture of the branches, so it's clear whether they, too, are infected with something, that would be helpful.

Thanks for more information!