Worried about an Old Friend

I am worried about an old friend. Without going into many details, I know this person is being mentally abused right now terribly. In my opinion, when someone is in a relationship and one of the mates is over domineering and controlling, life can be like hell. People should really be thankful for their mates and show them love, trust and respect. Many people do not understand that when someone has been in a relationship as described it is not always so easy to leave it. We speak of women being abused but some men are too. Usually the person performing these acts are extremely jealous which goes hand and hand with insecurity. Myself, I could not handle a second if someone could not trust me five minutes alone to gather my thoughts and have my own private time even if it was in the bathroom.
Hang in there P.