If he's in the military, he may be able to get in. Please check with the museum.
You need a same day pass. They can be received after 1pm on weekdays if there is availability.
So I don't know. I am not from DC
Best chance of getting in without a pass is to get there early and be waiting in line for them to open. This month you don't need a pass during the week. I don't know how the same day passes work on the weekend.
I don't think the museum monitors Google. You'd need to contact them by phone. But, last time I went, no pass was needed...
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