Trying to create a custom field that works similar to "Contact is Deceased" function
Some thoughts.

Since 'is_deceased' is a field on the contact table i wondered what would be the effect of assigning a '1' to an Org.

The record does now show with DECEASED in red after the Display Name

The contact does show up if i search for is_deceased via Adv Search

I then also set an Individual to Deceased.

Neither of them showed email as On Hold nor Comm Pref as Do Not Mail.

When I went to print a PDF records for the Deceased (both Org and Ind) were printed

I got a whitescreen when I tried to do an export using " Exclude contacts with "do not mail" privacy, no street address, or who are deceased."

Some of the above does not gel with my Answer at What is effect of marking contact as deceased? but I haven't compared with dmaster.

I suspect an extension could make the is_deceased field show for an Organisation and based on above I sense that it would then operate similarly for both Ind and Org (though clearly my testing above didn't give me the outcome i expected for Ind in some cases)

Above was all done on 5.10.3 (ish)