I'm confused and frustrated by my postdoc mentor's stubbornness and not caring for my future at all. What should I do?
The way you describe your relationship, it sounds like manager and subordinate employee. Regardless of anything else - if that's the dynamic, it would not be surprising he expects you to follow his (effective) orders, and not very interested in promoting your independent future.

I know that many research groups have this dynamic; so it's not as though it can be easily rectified in favor of something else. Still, that's not how a post-doc is supposed to be like - and that depends on him, but also on you.

The way it's supposed to be (*) is:


You're an independent researcher on your own right. Even when you're part of a group, you're supposed to have your own agenda regarding what you'd like to study.
The post-doctoral researcher position is not the same as a 'senior research assistant' or a 'research support engineer' position. In those, the researchers' needs and desires define what you occupy yourself with, almost solely.
As a post-doctoral research you should already have developed, or should now be developing, independent relationships with others in the research community, outside of your group, and the collaboration with them - direct, not just through your research group.
(the part you like) A senior researcher should help his post-docs with their personal development as researchers - but not in a close follow-my-lead-closely relationship as s/he might have his/her MsC/PhD candidates.


So, he's not upholding his side of what's supposed to happen, but frankly - I believe you might not be, either, and what's more, it seems you had not clearly agreed beforehand on a reasonable modus operandi between you two; so you're expecting one thing to happen and he's expecting another.

The bottom-line suggestion is to try to arrange to have a "state of our relationship and mutual-expections-alignment" talk with him that's independent of any specific single issue or grievance any of you might have.

It's hard to make other concrete suggestion without information about your research group, your field, your departmental/university politics etc.

(*) - Again, some would argue that post-docs as plain subordinate grunts with a brain is a valid arrangement. I disagree.