Hello and thank you for contacting AaE for help.

It appears there are a few problems with this tree.  Some sort of damage and a couple of fungal issues.

First, Apple tree trunks can experience winter damage and I suspect that the long wound in the bark may be as a result of that.  Is the wound facing southwest?  That is most often the side of the tree that can be scalded by the sun reflecting off of snow in the winter.  If so, I suspect it happened several years ago.  The fungal growth in the cavity indicates decaying heartwood.  The tree will weaken but it may take a few more years before it either dies or falls over. 

It may be important to determine what caused the tree to crack open and the bark to peel off in case it is not sun scald.  Depending on the disease, it may be best to destroy the tree so that the disease isn't spread to other trees.

The spots on the leaves and the browning on the apples indicate that it may have Apple Scab.  This is a fungal disease that is usually not fatal; in fact, Honeycrisp trees are resistant to Apple Scab but can exhibit the symptoms if it's a particularly bad year or if it is already compromised.  I suspect the latter.  Apple Scab is a fungus that overwinters in leaf litter on the ground and then sends spores back up into the tree during the spring rains.  A wet spring creates a perfect environment for it to manifest the symptoms of spotting on leaves and fruit.  Some years are worse than others.  I think this may have been a pretty bad year for some.

There are some steps you can take to reduce the likelihood of your tree getting Apple Scab next year.  First remove all the leaves that fall from the tree during the spring and summer and dispose by either burning or burying away from any apple or crab apple tree. Second, rake up all the apple and crab apple leaves in the fall and either bury or burn them.  It's good hygiene that helps keep this disease at bay because there will be very little spore production that can get back into the tree next spring.

For more information about Apple Scab see the U of Mn Extension web page that describes the biology of Apple Scab and various management practices.

You may have noticed that I said your tree may have been damaged and may have Apple Scab but to get a definitive diagnosis, you may want to send samples to the U of Mn Extension Plant Disease Clinic.  Here is a link to their web page that provides information about their services and pricing.  Alternatively, you may want to have an experienced tree care professional analyze and diagnose the tree and suggest remedies.

Good-luck!