Its as 'safe' as clear text communication CAN be.

He will most likely get SSL (https) up and working again, but it isn't an automatic process. He will need to re-issue a new SSL cert for the new server. Depending on his cert type, etc. etc. it could take a day or two or more.

With that said... if you aren't many hops away from their server (traceroute to the server to find out) and your network is secure (local network) then you would most likely be safe. Yes you're always open to the possibility of a MITMA, but unless someone is specifically targeting you, or you are in an unsecured area with many 'hops' across internet land to his VPS server, then you'll likely be fine. If likely isn't good enough or you want to error on the side of caution, then I'd just say to wait until SSL is re-established. I would also NOT use TOR if you have in the past, however a VPN should be fine.