Thanks everyone for your encouraging words. In hindsight I'm so very glad I didn't say anything at the time. Nothing good would have come from it and in terms of etiquette it was the right thing to remain quiet.
Recently I was talking with a different friend, with two adult children still living at home (ages 25 and 27), about vacations. He was lamenting that he and his wife wanted to do a vacation with the wife's family but what had begun as an affordable $1,200 per couple trip had now morphed into a $2,500 per couple trip. He said that meant he would have to pay $5,000 for the trip. I was confused by his math and said, "I thought it was $2,500 per couple." He said, "well I have to pay for my kids to go so that bumps it up to $5,000." Surprised I said, "why can't they pay their own way?"
Oh my, you would have thought I said his kids were lazy dead beat drug lords. He became defensive, stuttered for words then snapped out, "well they live at my house and as long as they live there I'll pay for things! They can take spending money but I pay for vacations thank you very much!!!"
It was soooo awkward.
I've heard Dr. Phil say the stronger the reaction the more relevant the question or statement. I have a feeling there was more going on behind the scenes but it was so terribly awkward when he went all flash-defensive on me. Thankfully someone just happened to come into the room at that time and it eased the tension but, sigh, that was uncomfortable. I guess the general rule with entitled kids is to just ignore them and avoid conversations about them at all costs.