It sounds like early days both in your relationship with him and for whatever emergency he's dealing with. I can think of a few things that would potentially take someone out of work for a few weeks/couple of months so I doubt there's anything untoward going on, just the uncertainty that comes with emergent situations.

I know it feels like it, but the universe isn't conspiring against you, it's just life happening - and life happens to everyone, even really good therapists. In your shoes I would give it a week or so and check back in with his practice. He may not be back at work but they might have a better idea of timescales.