My father is stubborn, and becomes irate if anyone offers to help before he has decided he needs help, despite (or because of) the issues he faces as he ages.

"Good fences make good neighbors," the old saying goes, but not because it erects a barrier. It marks the point of trespassing. Building good relationships (like helping with the hedges) shouldn't be prohibited by those good fences. Bad fences split Berlin for a long time, and that's another matter entirely.