> Is there any way to set socket timeouts? I know there is deadlock timeout but this is not the case.

Yes, the property is called so_timeout and is directly passed when the
socket is opened (see Socket.setSoTimeout documentation). You can append
the property to the JDBC URL after question mark:

jdbc:firebirdsql:myhost/3050:/path/to/db.fdb?so_timeout=12345

Best regards,
Roman Rokytskyy