@bgoodreau01
You are looking at a very old publication. Pub. 553 was last published in 2009 for 2008 tax returns. If you want to "read the exact rules literally" you should read the current rules, not the rules from 16 years ago.
The current rules for Form 8615 are in the IRS Instructions for Form 8615, which I referred you to a few days ago, in an earlier reply above. The "exact rules" don't say anything about the child's expenses. They say "didn't have earned income that was more than half of the child's support." Whatever you mean by "expenses," it is not the same thing as "support." In particular, support includes tuition paid by the parents, and, as NCperson pointed out in one of your other threads on this subject, support also includes the value of housing provided by the parents. The Form 8615 instructions say the following (addressed to the parents).
"Your support includes all amounts spent to provide the child with food, lodging, clothing, education, medical and dental care, recreation, transportation, and similar necessities. To figure your child's support, count support provided by you, your child, and others."
It then refers you to Pub. 501 for details. In Pub. 501 see "Support Test (To Be a Qualifying Child)" and "Worksheet 2. Worksheet for Determining Support." You can use that worksheet to calculate the child's total support.
I suspect you will find that the child's earned income of $25,000 is less than half of his total support for the year.
You are correct that it doesn't matter how much of his support the child paid by himself. What matters is the amount of his earned income, no matter what he actually used it for.
You seem to be having a lot of trouble with this issue. Since your grandson is an adult, you are not responsible for the accuracy of his tax return. If your grandson is unsure about how to complete his tax return, perhaps he would benefit from consulting a local tax professional for help.
