You seem to be using DT 1.9 API on DT v 1.10 Please refer to the newer version of DT http://www.datatables.net/reference/
If I understand you correctly, you want to change neighboor filters (mark "no-data" options grey for example) when any other filter got applied. If this is correct, stick to
drawCallback
The logic you use in your code seems to be close to how this is tackled, I don't know of any DT supported ways on creating combo-box column filters and of updating them, so yes, every time it draws, check the filter, and update/recreate the combos.
If you are not chasing for DT 1.10, here is working plugin for DT 1.9 by Dylan Kuhn.