He cannot "kick you out" of the LLC. You have an ownership interest in it.
Signing tax returns without understanding them may (and emphasize may) be negligent, but it is not a breach of fiduciary duty when relying upon the specialist retained by the LLC to perform the taxes. (Remember, the accountant owed a duty to the LLC, not to this other Member).
In the unlikely event that you are sued over this issue, you would have the right to defend the action (and hopefully you could defeat it in a motion to strike or some similar motion before it even got out of hand).
If the other member continues to withhold licensing or other things that make it impossible for you to do business as an LLC - he is in breach of his fiduciary duties, and that is actionable, and he is liable to the LLC for the full value of the loss.
To defend your rights, you may be forced to actually have to file a breach of fiduciary duty claim against him and hope that you are able to finance the litigation and eventually collect.
It may be worth considering making an investment
in hiring an attorney to review your case and perhaps assisting you in negotiating this matter on your behalf now with a little more leverage than it seems he is bringing against you.