Hi ordered with bt on there website
There will always be a phone line, as that is needed for the broadband.
A physical phone is not essential, but is recommended. You do not have to leave it plugged in unless incoming calls are expected.
A cheap wired phone for less than £10. Its really useful in an emergency as he can dial 999 or other important numbers, and also to check if he ever has a line fault in the future, or a noisy phone line, which will affect the broadband.