You have some very serious burden there and I do not know if I can help you sort it out. I will preface my comments by reminding you (if you do not know already) that I am a CPA of many years and will be married forty years this month. The first point is to tell you that I deal with these things all the time, the second to tell you that I have some very real life experience.
For what seemed about half of our marriage, Rebecca and I whipped each other through our education - meaning, she would work while I pursued my education for awhile and then I would work while she pursued her education, and back and forth. The end result, I have two bachelor degrees and a master of taxation degree and she dropped out of medical school when we adopted our son some 23 years ago. She is an RN and a CRNA and has a degree in Biology with a minor in English. And now she works in my office. (Oh, and we did all of that with a minimum of borrowing for student loans). I give you all of that to point out that it is doable. As to borrowing for living expenses, I would advise against that because it is a very slippery slope. The very first thing you two should do is determine what it is that you want to do. What is your two, five and ten year plans. In separate rooms, you should both sit down and write out those things and you both have to know that there is no wrong answers here. When you are done, you need to take whatever time it takes in a space where there are no distractions and reconcile your list to his and his to yours. This can lead to some very meaningful communication. It is important to be honest and these can be very revealing (and relationship building) activities. Once reconciled, you need to determine how you are going to get there. Okay, wait for it because here comes that word that none of us like to hear. Now that you know where you want to go, begin to create a budget for getting there.
Once you have done those things, in my opinion, then you can begin to determine where borrowing might enter into the equation.
As a side note, airplane mechanics can do very well and with all of the government oversight, it is an industry that is well grounded. I did have my pilots license for some years and owned a single engine airplane, so again, I know of what I speak.
One other thing I will mention and then I have to get back to work (the boss is giving me the eye), more money does not make one more happy. Some of my clients that live paycheck to paycheck are far more happy than some that have hundreds of thousands of dollars in the bank. Money will not buy you that happiness. You have to find the happiness in the journey that you are taking.
So good luck - keep us posted - and remember that we are here for you.