"mental care" really… I understand your son is new to the environment but it's already second semester. He really has to just toughen up. Ive visited West Point and will be attending soon and its honestly not that bad. I think that this might not be the right environment for him if he's already struggling. This is no diss to your son as many people are born and raised with different temperaments and I have no doubt that he is smart seeing as he got into WP. He will be commissioned as an officer and be forced to serve active duty at the minimum until 2036 should he continue. If he really just doesn't like the program its would be better for him to leave and enroll in a nice state uni. Don't let sunken cost cause him to do something he can't handle and exacerbate his mental health issues.
Tbh though he might be fine and just be ranting to you as an outlet since family are really the only people cadets can freely complain to. Encouragement will help him a lot more that feeding into his "depression". If he is a competitive person he can also be motivated by the fact that he was selected by our nation, few will have a service academy experience and the grit that comes with it, and people less mentally and physically capable than him have made it through a harder West Point (violent hazing, no modern amenities, etc) and made it out just fine.
Please just try to encourage instead of feed into this mental health stuff as it inadvertanly just brings down his morale.