Provided the line isn't fully unbundled (OneTel is owned by TalkTalk) he should be able to get broadband from PN.
What does the
Sam Knows checker say? Provided there are results against BT ADSL listing the speeds he's able to get then he should be OK.
If it just says ADSL is available and the exchange is Max enabled then it's likely the line is unbundled.
plusnet BBYW Pro