At least in Germany, while it's in principle possible to sue the employee for damages, it is very difficult to succeed with that if it isn't downright sabotage. You can't force the employee to work, it quickly goes into negligence on your part if you can't handle an employee going missing, ..., so you'll probably not reach much more than the salary - and for that just terminating the contract early would be easier, either in agreement with the employee or one-sided after they stopped showing up.
In that particular case, my experience tells me the guy won't get any credit for finding a solution, I would consider sick leave. Burnout, whatever. Doesn't have any monetary consequences in Europe (at least no harsh ones), and Germany covers up to 6 weeks of salary.
Any way, you can forget about getting goods references. Not that would get them anyway, with an employer like that.