Re: Sticking windows
I use only oil paint on my sash; remove them to sc****, heat gun and sand all the old paint from the sash and their "ways". I let the paint dry for a week before re-installing, and they glide easily.
Problem with latex is even when cured it is able to stick to itself upon contact especially if humid. So, it's like always having the windows painted shut. If you had interlocking metal weatherstripping you could set it up so there was never any paint on paint contact; it's a labor-intensive job, but the energy savings is good, too.
Remove not the ancient landmark, which your fathers have set.