Ornamental cherries and the rest of the prunus family are subject to a host of insect pests, especially borers, and many other maladies. It's really pretty rare to see one as large as yours because of they are relatively short lived trees in addition to their other problems. A tree service company is probably your best course. Don't be surprised, though, if they recommend removal rather than treatment.

i am not a bark specialist... it looks like a tree moving toward maturity .. or was .... i was referring to the trunk flair between the trunk and the roots ... which should be just ABOVE soil level ... sand is probably.. in my estimate.. the best thing to grow trees in ... drainage.. which is a clay problem... can kill a lot of things ... if you scratch a branch.. in young bark ... is there any green under the bark ... that is the cambian layer.. the blood system of the tree [in simplistic terms] .. moving food down to the roots.. and liquids up ... if it is black.. or missing... that branch is dead ... try elsewhere.. but dont get carried away and scratch up the whole tree ... the weeping part of the tree was grafted to a standarnd ... it looks like there might be some suckers coming from ground level.. they will NOT be weeping trees.... if everything above the graft dies.... you probably do NOT want it there ... if you do find green... you may want to wait until spring.. to see if it buds back out... do you see any buds at this time... sometimes.. for reasons never determined.. a tree will go dormant early ... but that usually happens in severe drought.. which you say didnt occur ... i am at a loss to go much further for you .... its bargain time at the bigboxstores and nurseries... if you are leaning toward replacement.. now might be the time to save some money on replacement ... if you can get decent stock.. that hasnt been sitting in the parking lot all summer .... in the alternative.. if its going to drive you crazy for the winter.. wondering.. fretting.. worrying... it may be better to be done with it now .... tough choice... good luck ken

i am having a hard time with the darkish pix ... but will try anyway .. but a few things first... OF COURSE the leaders are bowing... its a WEEPING PLANT .... dont get too frustrated by its natural tendencies ... in the long run ... the thing will kinda heap upon itself.. and achieve height ... next .... this will be a 10 year project ... you will NOT kill it by pruning it.. only by lack of proper watering ... finally ... the job is NEVER done.. on one pruning ... if you can NOT figure it out.. there is always next year... just stop.. put down the clippers.. and walk away ... i would rather you 'wait and see' .... than try to re-attach a bad cut.. lol... anyway ... first pic .... I THINK i see one rather straight branch/leader on the right .. WHICH I PRESUME goes down to the ground.. and the left one goes on a 45 degree angle out.. then develops the second leader.. this is a future weakness ... IF THAT IS A CORRECT INTERPRETATION .... as that 2nd leader grows in size .. it MIGHT collapse the 45 degree angle part ... so i would take it off either at the trunk or at the ground ... as to staking.... insert a stake .... TWICE AS TALL AS THE PLANT .... or as tall as you want to train the plant... on the side opposite the weep .... and then pull the weep to vertical ... if you need more than one rope... you are probably pulling it too far... and the placement of the rope it too high ... tie it... come back in a month.. retie it... another month.. retie it.. etc .... i prefer to use all cotton clothes line ... as it is easy to tie and untie.. and retie ... which you should do 2 or 3 times per year ... at least .. i tend toward cotton.. in case i forget for 5 years.. the rope will rot way ... same with jute .... if god had meant for you to use plastic twine.. your plant would be plastic .... you tie very loosely ... and you do it in increments ... thought with this whip, i doubt you can break it .... the whip should be free enough to blow in the wind .... but tight enough to guide up ... if it bows some other way next year ... pull up the stake and start over ... as i said .. training a plant is not really a once for life thing... you have to fool around with it.. until you attain your goal ... all that said.. i once bought said plant.. in a plastic bag... probably 4/2000 ... it fought all attempts at pruning ... basically killing off every leader i tried to shape into my preconceived notion of verticality ... so i have been ignoring it for 5 years.. and it did it all just fine on its own .... i just go in a prune out dead branches ... and in 8 years.. it has never bloomed ... it is east of a box elder ... and does not get watered ... so it is shaded for half a day ... its a nice plant... but i lost interest in it years ago ... if it ever blooms.. i will be thrilled.. but i am not going to fixate on it ... the reason i tell you this .... relax ... do what you can to train it ... but let it do its own thing... in other words.. dont set your expectations too high.. or you will never be happy .. good luck ken

It's pretty common for mice to girdle a tree like that, and it's usually a death sentence. If you catch the damage right away you can sometimes save the tree by making bridge grafts, but they don't always work, and it sounds like this tree is past the stage where you could try that anyway. If there is no sign of buds swelling by now, then your tree is dead. The next time you plant a tree you should wrap the base in chicken wire to prevent the mice (or whatever) from destroying it again. Also, keep mulch away from the trunk - several inches of cleared ground is usually enough to discourage mice from going after the bark. Is it possible that the tree was girdled last summer, when you noticed the leaves dying and that you only noticed the bark damage now? If that's the case, then there's no hope in heck of saving the tree - it's long dead :-( BP