Are you talking about your being in a Grand Suite or higher level, and wanting to bring a friend into the lounge who is in a non-suite cabin? That is not allowed.
They have tightened up on this across the board. Example: If a person is a D+ member and in a standard cabin they get concierge access as a C&A perk but if they are traveling with a non-family member in the same cabin that person is not allowed in. Same goes for access to the Diamond Lounge. Cruise Fanatic had this happen last month I believe.
I think it used to be that whoever was in a cabin got the same level perks as the highest level person in the cabin, but now it stops at familial relationship. But in all cases, if they are in a different cabin they only get the perks they have personally earned. Which as I understand it means that my son gets Diamond Plus perks (concierge access) when we cruise this summer in one Junior Suite. But if he is in an adjacent cabin he will revert to Diamond member because that is all he has earned and he is 18. It is sort of a confused mess.