My husband died in November and I so I just went through this with AA and TWA. I had to send a copy of his death certificate and a copy of his will. Since I was his beneficiary I had no problem even though I never had the will probated because the only thing we didn't have jointly was FF miles. I had no problem with TWA. They processed everything very quickly and were really very nice. On the other hand, AA took several months, many phone calls and $50 to do the same thing. In the end they did transfer his miles to me but they made it a rather unpleasant experience.
Actually, TWA didn't even ask for a copy of the will. They accepted the copy of the death certificate alone. Of course, the address was the same on both accounts so I guess they didn't think I was trying to steal the miles. Now, if all works out well AA will sometime in the future combine my TWA and my AA miles and I'll be finally finished.
Chris