@Nonso, i agree with you.
The posters above has said it all. Meanwhile, there shouldn't be any problem as long as she (your friend) knew how wrong her past action was and did also showed a considerable level of remorse. Furthermore, as long as your brother have confirmed through medical advise (as expected of serious dates to must have had a medical checkup) that she is perfectly alright then you need not worry. Let them enjoy their happiness.
Leave 'em alone....tz dia biz nt urz tho....yhur frnd myt b a bad qurl [wich yhu've noticed] buh myt chanqe afta marryinq yha brava.....yho cnt decide fate, leh |t decide |tself
If u were in her position, won't u wnt d guy 2 get married 2 u.? Jst ask her if she has told ur brother