Oh no! I realize that... but you're offering him the knowledge, confidence and support he needs to be able to make a lasting and positive change in his life.
If he's on £17k/pa and you're billing out £350 a day, then he only has to work 50 days per year to come out in the exact same place he's in now.
As long as he gets from you a list of those "first steps" on how to find the contracts. Even if he starts out billing only £50 per day (for fear of not finding work, in order to build a client list) he'd literally be no worse off than he is now (of course rent in London is much higher so ... I think he should at least bill £100/pd).
It sounds like he is a skilled developer with some niche knowledge in the auto market. Suffering perhaps from a lack of confidence (are my skills really worth that much?) and a bit of Fear, Uncertainty, & Doubt (If I quit this hell-job will I have to go on public assistance? will I be homeless?)
He's got to make the leap and get out. No question of that in my mind ... but he also needs help and encouragement to do it.
That's what I saw you offering (not the job) ... it's just the seed of that mighty Oak that I've seen planted - but - I've already assumed that there's a happy ending to all this.
What can I say? I'm a dreamer and an optimist. Probably why I spend so much time reading HackerNews :)
Teach a man to fish and you've fed him for life.