Re: pharmacists
I'd be surprised if one staff member's errors really were enough to push a pharmacist into resigning from his position... There's probably a lot more to it than your colleague's repeated errors: pressure from management to achieve targets (MURs, script figures, etc...); lack of rewards (financial or otherwise), working atmosphere, travelling distance, lack of working hours flexibility, career options,...
I agree with Web Ferret: you shouldn't say anything to your colleague, it's not your place, and it would only poison the atmosphere...
Ze genuine Article, present & perfect!