Extract Data from a dead GW Server possible?

One of our customers "was" running a Groupwise Server (v18) on SLES for one of their customers, until a couple of days ago. The server cannot be revived, at least not with our limited knowledge. Unfortunately, that customer has very limited GW knowledge either and consequently.... no backups

Is there any way to extract data, mostly calendar, from several accounts from that dead server, or the database files?

Thanks for any pointer