Unfortunately there are some frum people doing time for such crime. It is 100% illegal and taking the chance is riskly. Perhaps he/she is really not your friend but wants you out of his/her way!!!!
Let this person get in touch with Renewal, an organization that helps people in need of a kidney and it is all l’shem mitzva. On one of the grant sites, it lists howmuch they get annually. So it is all government funded and no soliciting is really necessary.