Basically this,@Comewithrealness let the girl have her future“Whoever conceals [the faults of] a Muslim, Allah will conceal [his faults] in this life and the Hereafter.”
In an enviroment like the west its easy to sleep around,especially when you are young and naive,if she is matured now,she went back to her deen and dhaqan its good,buutttt if she still has tendencies then tell on that ,if she was a then i hope they go get tested first
Give him hints,because of love he might turn on you instead,