how do i help

Our clan was in a similar situation. We are a mid-level clan with a lot of members who are lower level as well as  FTP and who don't spend a lot of time in game. At the time we had roughly 3 members who were 2 keying NM and were ready to move to UNM. Our strategy was as follows: 

We chose a date the week before and announced to our clan that we wanted to take down NM CB. (The day prior to a CvC that offers personal rewards is a good time so everyone gets the points from the 2X chest.)
We put this date in our discord as well as the "Clan message of the day" and we posted reminders all week in Clan Chat and in discord.  

On the announced date our stronger members held back and let our lower-level members do as much  damage as they could. Once we saw that most of those players had used their 4+ keys then our stronger members finished CB off using gems for the extra keys we needed. If I remember correctly, I and the other 2 higher level members only used 3 extra keys (300 gems) each to defeat him. I was supprised to see how many of our more casual players pitched in with extra keys as well.

Rather than have someone come in and kill it for you maybe try and defeat it as a Clan.