What all do you know about the Roswell ufo story?

Worked with someone whose mother was a retired nurse. His father had been in the military and she befriended a military nurse. This nurse told her much later after the Roswell event happened that she was assigned to the area where one of the aliens was kept and was barely alive. Another one had died. They were the small grays. This nurse was threatened by military intelligence never to tell anyone and they hinted that they would harm her and her family if she did. So she kept quiet until the Roswell incident became a big topic on shows etc. I guess she felt safe talking about it then.