Easy there big guy…. Remember that FIL and MIL are the messed up products that helped to create the mess you’re in (via your wife), so jumping down FIL’s throat will probably get you similar results to what you get with your wife. You’re way smarter than that.
Not being the nice guy doesn’t mean you need to be the bad guy. Look at this situation in a different light…. take this as a golden opportunity to work on your marriage. Your FIL is out of work, so how do you think he feels? Pretty bad, right? You are empathic to that, which is good, but you are also way above his situation in a way. You may think of yourself as just a struggling professor, but I doubt he sees you that way. He probably has some envy of your education and the stability of your job and your future, especially now that he is feeling the sting of unemployment. Each year that goes by you further cement your status and reputation at the school, with your wife and the in-laws.
He is probably very envious. I say this knowing that there HAS to be some FOO is his background, so his response to this envy will not likely be healthy. So he tries to pull you into the pit, get you off center, rock your world a little and take you down a notch or two. That might feel good to him, put you on a level playing field with him. Now this is all speculation on my part, but that might be one way to view him and keep yourself to a higher code of behavior.
If it is true, even in part, then you can take he lead here by staying your course in concentrating on your job and your responsibilities. You would do this with your kids, even if they were old enough to nag you to come home for some reason. You do have a higher purpose to fulfill, remember? So stick to your path and let your FIL be the one to get pissed off. Practice some boundary setting and calmly tell him how much you appreciate his help and hard work, but to ease up a little. Maybe create a building schedule that works with your job. YOU control this project and its timing. YOU set yourself out in front as the alpha male.
Remember all that training you were doing with Blackfoot? That applies to other men as well as your wife, especially your FIL. What better time to subtly sink some boundaries and that unspoken “understanding” between the two of you as to who is really in charge. No need to get upset, angry or tell him off. Start to use your skills. I think this is a great opportunity for your marriage. Turn it all around to work in your favor.