Very sad news.
I loved watching Dallas in the 80s. It was a show I watched regularly with my father as it typically started just as he arrived home from work, so it has a special place in my heart. JR Ewing was such a brilliant antihero: calculating, ruthless, relishing his notoriety and generally living a very twisted yet still enjoyable to watch version of the American Dream. Larry Hagman was born to play that role; he carried it off perfectly, bringing a warmth to the character. A couple of other posts call JR a Magnificent Bastard and I have to agree; he personifies the trope to a tee.
I never really got into the new Dallas, but I hope they come up with a fitting tribute to the character. Maybe JR could meet the Devil again, and this time carry out a hostile takeover of Hell...
As for Larry Hagman, who always seemed to carry his own personal difficulties with charm and humour, I hope he rests in peace. Thank you for all the great memories!