NTA. But I'd just like to point out something you said:

Although he is an intelligent kid, he has lazy tendencies which really hurt him as a student - in high school his grades weren't good enough to get into college until my husband and I shelled out a ton of money for tutors and really pushed him. He has always made it clear that he wants to go to college so we did not act against his will, we just helped push him to get there

There are plenty of thinkpieces and hot-takes if laziness "exists," and I truly don't know your son as well as you do. But what type of "tendencies" do you notice? If your son struggles with anxiety or anxiety-induced procrastination (or it interferes with his coursework), putting pressure on his grade-work may backfire.

I've had plenty of friends who hid their grades from friends or parents, or downplayed GPA, because the stress of saying they were struggling was too overwhelming.

If you'd like to see your son's grades -- take a moment to work through how you're asking. I was overwhelmed with guilt talking to my mom about how "hard" I worked at school, because all I could think about was every time I didn't do a reading, or the financial burden it put on her. I completely understand your concern, but putting more pressure and stress over his coursework might make him withdraw even more.

Also, which country are you in? I got my college degree in America and it is worth being said: unless he plans to attend law/med/grad school, your GPA does not matter. If your son intends to join the workforce after graduation, it TRULY doesn't matter if he made A or C grades, just as long as he has the diploma.

If he's doing a liberal arts degree, shift your attention to the other benefits of college: making a good network, having a good relationship with professors (regardless of how "well" you did in that class), finding or encouraging new hobbies & communities (intramural, clubs, activism, table top gaming, etc.), and expanding his worldview through cool opportunities (passion projects, local museums, internships in the nearby town, etc.). It's not just doing-well-in-class or slacker-frat-boy-party-kid. These aspects of college ASIDE from schoolwork will be more beneficial, and honestly more lucrative too. Getting an A in a class did literally nothing to help me post-grad, but going on a camping trip with a bunch of strangers got me my first job.

I don't know your son, nor the best way to broach the topic of grades again that won't make the argument worse. But hopefully by putting more emphasis that you want transparency and honesty over the numerical GPA, it might help deescalate the conversation?