Im in need of some advice...?

The ped 3/4 weeks i have been helping my bf bro which my bf is ok with me helping him out with finding him a girl or at least someone that is better then his ex who smokes weed (that her mother grows and sells) every night and want nothing but 24/7 and is lazy and crys for him all the time. So I helped him find this girl that i knew and she was useing yahoo personals as was he was too. So for the ped 2 weeks they have been nothing but talking non stop every night, till who knows when. Any ways the past 3 nights his ex has stoped by his place (were she lived for a year with his parents)talking to him till who know what time . I found out from him today that his ex and him were talking till 3am last night outside and then she spent the night. and left at 9am today. This girl who i found/knew for him see's some thing in him, she a church going, wait till marrige, loving girl. His ex is beging to get with him badly and i see it almost happeing and i dont want her hurt.