I feel your pain. I have 3 sons, two of whom have already graduated from college, one is a college junior. All 3 were high school honor students/NMFs, etc. Two of my sons are/were heavily into games/near addicts. One is on a college gaming team. I am not at all happy about the time my kids have “wasted” over the years on gaming. I think of opportunities they could’ve had for other experiences–other social activities, sports, working, service, developing other talents, study, etc., but I have to let them go make their own decisions/mistakes.
The “non-addict” (he plays games, but not as much as the other two) graduated with honors. The other two could have done/be doing better, got/getting 3.0-3.5ish. I do think it is fine for parents to be concerned about grades, check on them, set limits for their college kids. My junior son knows that if he loses his scholarship, or gets behind, I will not pay extra. So far, he’s getting by. Just frustrating to me because he is underachieving and gaming is the reason. S doesn’t have a healthy, balanced lifestyle. I wish he did, but I’m not in control of that.
I don’t know if it is time for midterms yet at OP’s son’s college. It is not uncommon for freshmen to do poorly on a first test, and then realize how much they have to study for the next one. Sometimes the instructor makes the test too hard and the whole class gets low grades the first time. OPs son may still come out with Bs and As by the end of the semester. First semester is such a big change from high school, so he may have had the same grades whether or not he was gaming. But capable students should not be getting semester C’s. You will have to wait until December to find out. At least you know what is going on early in the semester. Reminding him to manage his time wisely–make sure he knows where to get tutoring or any other help he might need–and letting him know that you care about his performance, is probably all you can do.