I am not an expert on Boeing. I did have (for me) a large position in their stock for awhile, which means I did some research, but I never worked for them, so I don't have an insider's view. (When the details of the 737 MAX problem and the background was revealed, I sold everything, as I lost trust in their ability to execute. I sold at about $380, and was pissed that I missed selling at the all-time high of $440, but now that it's trading at $95 I'm more satisfied with my decision, ahem.)
Boeing's commercial aircraft development owes very little to the military. The military does buy some commercial aircraft for their own use, but as a percentage of total commercial aircraft sales it's pretty small. There is the case of the KC-46 tanker, which is based on the ancient 767 airframe, but that was a case of the commercial division subsidizing the defense devision, not the other way around.
(As an editorial aside, the KC-46 is another fiasco, but in this case Congress, the DoD, and Boeing conspired to make sure Boeing rather than Airbus, who appeared to have a superior solution, won the bid.)
Boeing's commercial division is more profitable than Airbus's because between the 777 and the 787 Boeing sold more wide body aircraft than Airbus does. Wide body aircraft have higher gross margins than smaller aircraft. And Airbus made a very unprofitable bet with the A380. If Mark is correct about international travel being permanently suppressed due to COVID19 then the tables may turn, because Airbus's narrow body planes are more successful than Boeing's.
Both of these commercial aircraft manufacturers are highly subsidized, but not by defense contracts. They provide numerous lucrative jobs in their manufacturing plants, so federal, state, and local governments (and their international equivalents) provide rich subsidies on their own.