@QRFMTOA - you are responsible since you own the 529 ( your son is a beneficary). any tax or penalties goes on your tax return.
Simply, whatever EARNINGS are dsitributed are subject to tax and penalties, unless there are "Qualified Higher Education Expenses" that support the distribution.
look at the link below - page 50 right side. - for a list of what qualifies, which are slightly different and more liberal than Qualified Educational Expenses" (QEE used for AOTC and LLC credits)
https://www.irs.gov/pub/irs-pdf/p970.pdf
