So you've got 5% going into the 457 already, take the remaining 10% and max out Roth IRAs ($6k each/year) for each of you (depending on what you make there may be some left over which can be applied to your 457).
https://www.daveramsey.com/dave-ramsey-7-baby-steps#baby_step_3
TDLR Version:
"Baby Step 3: Save 3–6 Months of Expenses in a Fully Funded Emergency Fund
Put this savings in your emergency savings or money market account so you won’t be tempted to touch it.
Baby Step 4: Invest 15% of Your...
I'm betting every kid at the high school got applied for those through said site. There's money out there but it takes work to apply for them (individual applications, essays, etc). The easy money goes fast.
There's a lot of scholarship/grant money out there that he can apply for to offset the cost of school, not to mention a part time job while going to school. Also consider public universities vs private that generally cost at least 3x more, unless you are going to MIT or Stanford a degree is a...