Nick Carter Emotional Ahead of Aaron Carter's 1-Year Death Anniversary

Nick Carter is remembering his younger brother, Aaron Carter, ahead of his one-year death anniversary ... and it's clear the tragedy still haunts him, 'cause he's choking back tears.

The Backstreet Boys singer was doing an interview with E! News Friday to plug his new single -- and they asked him how he was coping with his sibling's passing almost a year out. As it turns out, NC is still shaken by it ... and you can tell by his reaction here.

Check it out ... gets visibly emotional remembering Aaron, and he even reveals they were at a point of trying to reconcile their fractured relationship before he died suddenly on Nov. 5.

In other words, he's still very much grieving -- and he goes on to explain that this time of the year (right before the holidays) reminds him of not just family memories with Aaron ... but the fact that his baby bro lost his life during this period too.

As Nick says in this interview, he continues to process Aaron's death ... but still can't quite make sense of it -- although he hopes to get clarity one day. The same can be said about other people in Aaron's orbit ... including his GF and the mother of his child, Princeton.

We broke the story ... Melanie Martin filed a wrongful death suit on behalf of her and Aaron's infant child -- alleging there were a number of parties responsible for supplying Aaron with meds that were dangerous ... and which ultimately led to him drowning in his bathtub.

As we told you, Aaron's official cause of death was tied to Xanax and huffing.