I would definitely file to request a bond redetermination hearing to attempt to lower the bond amount. However, depending on which judge he gets, the focus will be on what relief he has available to him. If he doesn't have relief other than voluntary departure, then it's possible that the Immigration Judge will leave the bond at $10k. I recommend that you coordinate a consultation with an experienced immigration lawyer asap.
Best of luck.
Verdin Law Firm, LLC