Co-executor not doing the right thing.

If your co-executor can act alone under the terms of the will, unless the person is doing things that are violating the law or the will, or unnecessarily costing the estate money, there's nothing you can do about it. If the co-executor is stealing from the estate, or unnecessarily costing the estate excessive money, you can bring a proceeding in surrogates court for an accounting, to have that person removed as co-executor, and/or surcharged (fined) when the final distribution of assets is made.