I can see no Christian fraternity in a friend who warns you: “I’ve been told some terrible things about you. You shouldn’t trust someone among those close to you.”

I think it is not Christian because that “brother” has not had the noble reaction of silencing the slanderer first, and then telling you his name out of loyalty.

If that “brother” does not have the strength of character to demand such behaviour of himself, he will be risking your being left on your own, driving you to distrust everyone and to be uncharitable towards everyone.