i'm taking over my son's laptop and want to remove his song files and transfer from my iphone to the laptop.

If you connect your iPhone to the laptop, it will give you the option of transferring iTunes purchases from the iPhone to the laptop, or to completely erase the iPhone and sync it with the songs on the laptop. It sounds as though the former option is what you want.

Song files on your iPhone that did not originate from the ITunes Store will not be transferred to your laptop. To do that you will need to copy them from wherever they came from, which was not the iPhone.

If that source is no longer available, you will need to find some third party utility to extract its content. For some suggestions read wjosten's procedure here: https://discussions.apple.com/docs/DOC-3141