Two good touchstones for modern day or 70s/80s set westerns would be:
No Country for Old Men
Hell or High Water
Justified of course, but it's tonally a bit different from the above
BUT lets not get ahead of ourselves, because that could be GTAs territory.
They should continue with Jack 1910-1930 or until the child is old enough. Then continue with the child in it's 20s again (1930-end of WW2).
That could be 4 games, 2 with Jack and 2 with his child as the protagonist.