People without edit privileges on the site, as well as mods from other sites, cannot help (mods from other sites are just normal users everywhere else).
A CM could certainly help. However, this is probably not a good idea in the long run: In the bigger picture sense, if a CM has to step in, this isn't solving the site's real problems, and a CM can't be relied on to keep a site running, it has to be self-sustaining.
However, what we, as normal unprivileged users can do is: Spend some time on the site. In particular, visit the site, ask good questions, answer unanswered questions, vote on questions and answers. I don't mean randomly casting upvotes, I mean visit the site and participate legitimately. This has a few benefits:
- Most relevantly, increased site activity = increased votes = increased reputation = empowering more of the existing users with moderation privileges (this is why low activity sites have trouble with community moderation).
- You may discover a new community that you'd like to be a part of, and you may even help turn around an unhealthy beta site's fortunes.
- You may learn a few new interesting things browsing questions. For example, there are certainly some interesting questions worth reading in the top-voted questions list.
In other words, the long term solution for these types of problems is to "heal" them at their source; do what needs to be done to help support a beta site. Everything else follows. For users who aren't normally involved in the site, this means potentially finding a fun, new community.
For users who are already active on the site, what you can do is help spread the word. Try to think of ways to attract more users to the site. More users = more voting = more moderation privileges all around. Things like community ads, asking good questions that attract good answers and new users (and potentially end up on the HNQ list), talk about the site in your blogs, tell your friends about it, etc., etc.