The elderly are the hardest hit by Telkom's copper cutoff, especially those who have hearing-aid compatible phones that plug into a Telkom wall jack.
For someone who just wants the closest and simplest replacement for a landline phone, maybe these are the best options:
1. Telkom FLLA (fixed line look-alike phone), not the one which is a VOIP phone, but the one which is a cellphone disguised as a landline phone. It has to be charged to work, can't plug into a Telkom wall jack or a router, camt' have extensions on it, and be aware of the rental charges and calling plan options on it (
https://secure.telkom.co.za/today/shop/home/plan/smartvoice-basic-pv/).
2. A basic/feature cellphone, not a smartphone. Keeps charge for ages, just dial a number on the keypad, press green phone icon to make/take a call, press red phone icon to end call. These cost about R200, but I am not sure if you can port your Telkom number to such a phone (ask Telkom).