What should I do if I see a fellow Corporal being singled out and belittled by more senior NCOs, but do not want to create too much conflict?

So what do to if ssgt's and sgt's dislike a cpl in the platoon and constantly belittle and demean the cpl while trying to find a way to fry or burn that cpl from disliking him so much, he doesn't have enough negative paperwork to be charged with an njp, the cpl is been told that he doesn't deserve the rank and should not be one, when junior marines go to that cpl before anyone for help or advice and also the junior marines see how the cpl is treated and the junior marines are always trying to help the cpl even when told not to. When the ones under the cpl say they learned more about their job than anyone else, show more respect to the cpl than the ssgt and Sgt, the cpl has tried to talk to the ones above him and explain things or ask for help/guidance but they won't listen fully or help really. People from all over the unit and people in the platoon think this cpl is mistreated and is singled out way to much while the cpl tries his best and keeps trying to get better and wants to re-enlist but is worried the sncoic will not sign off on it. Plus the cpl is given a hard time when medical appointment comes up, and when family issues comes up but has to beg for a little free time, when the cpl gives up chow and stays late to do what he needs to, the best he can, as someone who sees this ever day what can another cpl do to help withput creating to much conflict ?