I think it is too early to give up on D1 but I would start to build a list of target schools in other divisions. He may realize that he'd be happier at another school in a lower division. Other divisions might be slower to respond and likely won't offer until the summer, but at least he'll have some conversations going and get a feel for schools to target. This summer I watched a lot of 2023 parents trying to pivot in August and September and missed a ton of showcase opportunities. Most of them are still trying to figure it out.
Now is the time you need to start figuring out your strategy for the summer. If it were me, I'd focus on playing in the big July tournaments and plan to showcase/camp in June and possibly August.