Suggest Treatment For Complications During 16 Weeks Of Pregnancy With Twins

hi
my wife was pregnant with tts twins for 16 weeks when they realized .we did the lazer surgery and then 3 days later they said it was really improving. 3 days ago Dr said he couldnt beleive it . the baby that was originally receiving the blood and the one that was giving(originally weaker). the receiver has no more heartbeat and no more blood circulation. has there ever been mistakes or you think this is it.
thank you