No, and retired military is only allowed on Mon-Thur.
Commissary is closed on Mondays. I've never heard of certain days retirees aren't allowed to shop there. They may have removed the "early bird" shopping for seniors (30 mins before regular opening) due to COVID-19.
Yes as long as the retired person has an ID card, they can sponsor the non military person onto base. And the retiree can use the commisary any day of the week as long as they have their ID card. I am retired military and I can get on base any day of the week as well as use commisary.
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