That's fine and it wasn't personal just a fact. I did do an apprenticeship and your right I was at home with no other worries. What they show you in college will not teach you much. I promise you that you will come across systems that wasn't in the textbooks and problems that were not in the text books. Then what are you going to do with no one there to help you out? Tell the customer you have no idea? You'll be out on your ear with a bad reputation before you've started.
JCS - With regard to not having anyone to help out if things aren't what they seem - I did a Government training course at a Skill Centre in Reading C1982, then straight into plumbing (I call this my apprenticeship but I know that it's not the same).
Yes - it can be difficult and it was, in part, however in this day and age one can peruse the Internet and locate all sorts of information through forums such as this, and once working in the trade, relationships are built with others who might, just might be your 'Phone a freind'
With regard to changing careers - I made it up the ladder to site foreman, without help from a mentor, and then became discouraged after being made redundant so I changed my career and, against all the odds, I became a school teacher. I have a Hons degree in Fine Art and a Post Graduate degree in teaching Art & Design. I have rarely had help from others unless I have searched this out for myself yet I have made it this far, and I'm 58 in August.
I run my own business now and my work has increased 10 fold since starting in 2013 so I'm happy with what I do, and this is the main thing about career changes really - enjoy what you're doing, oh - and admit it if you don't know the answer. I always say "I'm not certain about this but I'll be back tomorrow with an answer". This will then be picked up by the customer and, as in my case, they will spread the news that there's a very happy, honest plumber/heating engineer who doesn't mind the small jobs or the big jobs. Before you know what's happened your reputation has grown and you're making a profit. Yes it's difficult but it can, and has been done.
If Ian wants to do this to have a better standard of living, or a better work/life balance then who are we to say he shouldn't. We are lucky enough to have this trade and as such we should (This isn't meant to denigrate your opinions or comments btw) encourage rather than dissuade.
As long as he's prepared for the hard graft at the start, and to learn from his mistakes, as there will be many, then he'll make it work for him.
Enough rambling from me - I've now got to drive the boss into work