Which Harry Chapin song? Love that guy.
As someone else mentioned, as long as he was direct about his intentions.....perhaps starting to discuss when each child was 12-14 or so, then it is not a problem. No obligation. His money, he can do what he wants.
Personally, though, I think the choice of having 8 kids and having less for each is somewhat poor planning. Personal choice. I am no fan of the Duggers, et al. Some of his kids will likely want to have careers/lives that require college.....perhaps the cost will cause them to choose something else. Again, no hardship, but perhaps he isn't doing the best he could.
8 kids is ridiculous....to me. I cannot see having 7 and saying "let's have another.....why not?" Again, personal choice, but geez.