I would do it if my D agreed that she returned the money to me later, because the loan is under kid's name, not parents' names. If the amount is not big, really no bother--the interest is equal to the loan amount*interest rate. No need to return until they graduate, right?
If you consider taking money out of your house equity, there are 2 ways.:
1. Home equity loan--the interests might be higher than your current mortage interest. You could consider a home equity line of credit if you are not sure you need the money. Just in case you need it, they this is a good way to be ready.
2. refinance--cash some out if you have more than 20% equity on your house. This way you will for sure to get a better interest, depending on the timing.
With one year to go for your daughter, brother, just look a little bit further, you can see the light from the end of tunnel. Be happy!