If your dad pays BT for telephony and Sky for broadband separately, that is a pretty rare legacy arrangement called SMPF ( shared metallic path facility ) and will present problems regarding an IP telephone service like BT Digital Voice , in essence with ‘digital voice’ you cannot have two separate providers on the same ‘line’ one for broadband and one for voice, because the BT DV service is integrated with BT broadband
TBH , it’s unusual that anyone on this SMPF arrangement is being migrated to DV so early in the program, the complications involved suggested that these would be amongst the last groups to be moved onto DV , but if your dad has received a letter, presumably the change is imminent .
You would imagine that the letter has more information as it cannot be like the ‘ standard’ communication from BT for BT Broadband customers, that simply states to move the phone instrument from the socket on the wall to the socket on the BT ( SH2 ) router on the appropriate day, obviously if he is a Sky broadband customer , he won’t have a BT SH2 router , so the standard communication for BT Broadband customers will be of no use.
It ultimately will be a choice for him to make , join BT for both services ( leaving Sky ) or join Sky for both services leaving BT .
Just read the OP again , why did I think the OP father had received a letter from BT ?
