I was wondering why we don't use the existing word, befriend, but perhaps befriend has too specific a meaning:
verb [ trans. ]Maybe when we friend someone on Facebook we don't want to enter into the complexity of a relationship that places any demands on us; we don't want to have to help out or support the other person. After all, the new Facebook friend might be someone we haven't seen for twenty years, someone we don't intend to see in person in the next twenty.
act as a friend to (someone) by offering help or support.