Depends entirely on his usage, how much his LL costs him now, and how much a suitable package costs. If he has a mobile already, then looking at a mobile only suitable package might be easy enough if you think about the all you can eat type packages. E-mobile do one for I think 70 or 80 euro a month which includes unlimited minutes, texts and data. Looking at something like that even might pay off, and thats before looking at the lower cost but limited minutes/text packages.
If he currently has broadband over his landline though it changes things considerably, as he would have to source a suitable alternative!