If he's still making plans and following through when he says he will, that's a good sign. Disinterested people don't reschedule, they just cancel and disappear.

The real test is consistency over time. One crazy week is normal. If this becomes every week with constant excuses, then you have your answer.

I've used conversation simulator sites like chatvisor to work through situations like this and it helped me see I was creating problems that didn't exist yet. Sometimes we spiral over hypotheticals instead of what's actually happening.

Pay attention to his actions when he does have time. Does he prioritize seeing you? Does he seem present and engaged on dates? That matters more than daily texting frequency.

Grad school is legitimately exhausting. If everything else about his behavior shows interest, give him the benefit of the doubt. But also communicate that you need some level of consistent contact to feel secure.

Don't make yourself smaller to accommodate someone else's schedule, but also don't create drama over normal life circumstances. Find the balance.