Hello,
There is CMD_API_BRUTE_FORCE_MONITOR available, but it's never was documented. So I guess you can use it, just check CMD_BRUTE_FORCE_MONITOR for required POST fields, which you will need to send to API link.
Some time ago we wrote a commercial addon for Directadmin, which allows user/resellers to unblock IPs earlier blocked by CSF/LFD, so if you are interested please drop me an email. It's not free yet, you will need to pay for it.