Our family friend is a commercial plumber with his own business and charges $150 per hour for his work and won’t let his son go into this line of work, why?

He told me it’s better to make $50k per year sitting in an office than $150k per year killing yourself. He refuses to let his son go into plumbing and he said to finish college and work a desk job is the ultimate dream for his children. I found this shocking. He said his body is beyond ruined and he works so much that it’s hard to have a stable marriage. He said he only got into this line of work because he didn’t know English well and couldn’t go to college due to supporting a family. I have a lot of respect for all you blue collar workers now.