Hello!

I'm sorry to hear about your tree.  From what I can see in your photos, the symptoms look consistent with Fire Blight, a bacterial disease of many members of the rose family, including both pears and apples.  Some varieties are more susceptible than others; a lab test would be needed to confirm Fire Blight for certain.

The best treatment options are preventative in the early spring during bud- and blossom-break.  Curative treatments have not been shown to be particularly effective, though you might see some disease suppression.  Attempted curative treatments need to be applied by a licensed pesticide applicator, and are usually only used in commercial orchard settings.  (You could find a contractor to discuss your options by using the "find a professional" tool at the web page of the International Society of Arboriculture, http://www.treesaregood.org).

For smaller infections like yours, pruning out the diseased branches can be effective at reducing or eliminating the disease.  You do have to prune far back from visible symptoms--18" to two feet--and this can leave trees looking a bit worse for wear at the end.   Pruning out the symptomatic portions will also help to minimize spread to other susceptible trees in the area, including your apples.  The disease can be splashed from active infections by water or moved by birds or insects.

This fact sheet contains more information about the disease cycle and particulars about treatment options: https://extension.colostate.edu/docs/pubs/garden/02907.pdf

I hope this is helpful!

Cordially,

John