Non-Qubes-Whonix 14 official builds will be 64 bit only. (But it will take a while until release so do not hold your breath for it.)
Non-Qubes-Whonix 13 official builds stay 32 bit only. As long as in place apt-get upgrades are possible, 32 bit users can stick with 32 bit, because none of Whonix packages were made 64 bit only. No big efforts will be made to carry around 32 bit users. Users who wish to upgrade to Non-Qubes-Whonix 64 bit need to download and import new Whonix 14 images.
Building Non-Qubes-Whonix 32 bit from source code will still be possible (as deprecation is not required), but not big efforts will be made.