only NAREIT investable?

By looking at alternative asset index, I find only NAREIT investable, the rest are not investable, is it true,

NAREIT is cap-weighted, what’s the difference between cap-weighted and value weighted?

no difference cap-weighting and value-weighting are the same.

can NAREIT be investable?

I think yes

NAREIT is a real time mkt cap weighted of all REITs