Perhaps he didn't know that mobile numbers all start with 8/9 (with the exception of our emergency service numbers)?
Some people don't realise that there are number allocations. Also, there are a lot of YP nowadays that don't even know that homes can have land line numbers - they grew up in a time when their friends only have mobile numbers, so they assume that only businesses/offices have 6 series numbers. Some have never encountered 3-series numbers even.
Their ignorance reflects on them.
No need to angst.