He is a higher echelon of friend, he is more than a friend, he is almost a brother, he is called mompirri to a very trusted person, for whom he has a special affection.
In Colombia in a colloquial way friend, parce, key, companion. Compadre , buddy .
MOMPIRRI in Colombia: colloquially, friend, mompa, contraction of mon partner or mon parce, in turn of the Portuguese parceiro, companion.