Yes! (Some!) window sash repairs are possible. This latch rail was probably destroyed by
a wood virus, not water rot or insects. So, overall, frame stiles were repairable with a
new latch rail inserted in place of the badly decomposed original. A cheaper, faster
alternative to the special order replacement kit which can take up to 3 weeks to arrive.
As Hannibal Smith famously said: “I love it when a plan comes together!”
This, of course, is not my first rodeo.
A previous wildly improbable wood damage repair can be found AT THIS LINK.
And here find TWO sash repairs from the wayback machine in the days before insulated glass!