I agree with Chris. And at this stage of proceedings, when all that remains to do is the 2pc, there isn't anything that anyone from INZ can tell you except, 'It is waiting for the 2pc check,' because when an outcome comes through, they will tell your brother.
You may not have realized what happens when the CO recommends an outcome and passes the file for 2pc. It will join a date-order queue of files from all COs from that office, and when one of the officials doing 2pc finishes the case they are looking at, they take the next from the front of the queue. The actual checking doesn't take very long at all. Most of the time when people think of their file as 'being second-person checked', it is actually sitting in the queue, awaiting its turn for attention.