Looking through job posting in my area I came across one that had the same job title that my father had for most of his career. I sent it to him and asked if the skills required and job description was the same as his. He agreed it was the exact description he worked. He said when his kids were born in the 70s he was making $20-something an hour, plus OT and union benefits. I pointed out this job was paying $15 an hour with no union.
It was finally the key needed to prove to him that we are not all complaining just for the sake of it, but because we are not being offered the same opportunities for financial success that they had.