Required Minimum Distribution Under QDRO

[RTK]

Participant and spouse divorce, and a separate account is established under a defined contribution plan for the former spouse alternate payee pursuant to a separate interest QDRO. Alternate payee has the right under the QDRO to designate the beneficiary for alternate payee's separate account, and alternate payee designates son as beneficiary.

Participant dies in 1997 (after separate account established), and spouse dies in 2003. Question: when does alternate payee's separate account have to be distributed to designated beneficiary son?

I dutifully read 1.401(a)(9)-8, Q&A 6, but I was not able to come up with a definitive answer.

I want to conclude somehow that altenate payee's death is to be used for required minimum distribution purposes, perhaps under 401(a)(9)(B)(iv)(II). If participant's death is used, what would this mean for distribution of alternate payee's separate account if alternate payee in this instance was still alive in 2004?