How do you sue a county jail for death?

My boyfriend commited suicide while incarcerated by an overdose of prescribed medication, doxepin. They said he expressed suicidal thoughts in the past yet they put him on a drug without making sure he took it, giving him the opportunity to save some for later when he took it all at once. I believe they should have monitored him better and even in researching this drug i find that one must be monitored if they have expressed prior suicidal thoughts or attempts. isnt there something i can do to let them know they were wrong and so that it doesnt happen to someone else? a href="http://www.timesdispatch.com/servlet/Satellite?pagename=RTD%2FMGArticle%2FRTD_BasicArticle&%09s=1031784331421&c=MGArticle&cid=1149189092154&path=%21news%21localnews" rel="nofollow"http://www.timesdispatch.com/servlet/Sat…/a