My friend recently starting dating a new guy from college; this is her first year. I recently found out from another friend of mine that this boyfriend is abusive, controlling, and overall a terrible person; she knows this because her step-sister and another friend of hers dated the same guy. I have talked to him before and he seems so nice so I'm scared to tell my friend from college about what my other friend said. I do not want to harm our friendship. What should I do?