It may be too late to show who is really the one making things happen. What should have happened from the very beginning is the lead engineer originating all correspondence and cc the so called manager. Also, any meetings with upper management, especially technical ones, the lead engineer should be present too. If the immediate supervisor balks at this, then one or two options remain. 1) Go over the immediate supervisor's head and put it in writing. 2) Time to be looking for a new employer.

There is the slim chance that upper management is purposely directing the immediate supervisor to behave this way. If so, attending an upper management meeting or two, as well as becoming the orginator of all communication will show which way it is.