As someone with a master's in engineering & a fATPL, and through speaking with people involved in pilot recruitment, I am not convinced you become more valuable the more facets you have.
It definitely makes you stand out from the pack and makes your CV more noticeable, but the vast majority of pilots don't have degrees. The (people) skills you learn at uni are not per se the same as they want you to display during the interview/group assignments/etc.
For example, I started flying after getting my degree and working for a few years. I have plenty of experience working with professionals/colleagues on long term projects worth millions, but when I was invited to an interview day, I had a group assignment with a bunch of 20-24 year olds. Lovely people, but oh so green behind their ears.. I certainly didn't expect that!
Get a degree because you want a solid backup plan, or because you want to develop yourself and gain a more worldly view. But I'd advise against picking a degree willy nilly just because you think it might lead to a flying job. It most likely wont help (directly), and 'aviation' degrees are a terrible backup plan should the flying not work out.
I hope this does not come across as being negative just for the sake of it. I hope you and your son figure things out! All the best!