Looks like the event was a great gathering and those photos are class.
Jock is coming home from South America and the family are celebrating his return to Dallas, with their annual barbecue. All Jock's friends are attending and big guns in the oil business, (a scene from season 4; DVD-5, 1981 - '82):
Ellie takes a phone call. The news isn't good, about the Ewing patriarch. J.R. is standing on the stairs and looks down at his distraught mother, clutching the phone.
J.R.: "Mama!"
Ellie: "That was Punk. Jock was flying in from the interior by helicopter. It crashed. They've been ...... they've been searching all day. Nothing! The locals have given up."
Ellie in complete water works mode (the poor woman): "They say that ...... oh they say that ...... they say that Jock is dead!"
The frame freezes on Ellie; then fade to black, the closing credits commence and the theme tune blasts out.
In the next episode the search is on for John Ross Ewing Senior, better known as Jock.