No , it doesn’t include SMPF customers, it’s for telephony only customers, someone with SMPF is self evidently not a telephony only customer, they have broadband from a non BT supplier , BT phone only customers using this solution will effectively be connected to BT Broadband equipment in the exchange, the is ATA ( analogue telephone adapter ) is also located at the exchange and the copper pair delivers ‘DV telephony’ without having the customer changing thier existing set up at home , they don’t have a BT router at home because they are telephone only BT customers.
SMPF customers do already have a router at home , one delivering broadband from the non BT source, you cannot have BT broadband connected for BT DV and someone else’s broadband for ‘internet’ coexisting on the same copper pair .
When the time comes , your relative will need to decide which provider to remain with , and which one to leave , AFAIR, it’s BT and EE in your case , and because BT as a consumer brand will disappear anyway , it makes the choice easy.
