Transfer Responsibility of Combined Billing Account upon Death of Spouse

My in-laws have a combined billing account - DirecTV, internet and home phone.  My father-in-law died, and my mother-in-law has continued to pay the bills.  She is now eligible and has qualified under the Affordable Connectivity Program (ACP) and Lifeline plans, under which she would receive discounts on her internet and home phone service, but I can't get those applied to her ATT account because it is still in her deceased husband's name.  

When I try to transfer the service using the ATT website, it only gives me the option transfer the internet and home phone, and when I try to accept the transfer it is rejected because it's a combined billing account with DirecTV.  

When I call DirecTV, they tell me they can't do the transfer without cancelling and restarting everything, which would lose her home phone number.

If I "de-combine" the internet and home phone services from the DirecTV service in order to do the transfer of the internet and home phone services, then I lose the combined discount on the home phone; and if I "de-combine" them, do the transfer, and then re-combine them, I can't get the discount because it was "grandfathered" and is no longer offered.

Is there any way for ATT/DirecTV to transfer billing responsibility for a combined billing account to a surviving spouse upon the death of a spouse?