Can mom apply for DIC although dad died in 2005

Question:

My father served in Vietnam for a year. Honorable Discharged. He died in 2005 from a rare cancer called Angiosarcoma. I have been trying since 2005 to get my mother to apply for DIC benefits. She went today and was told that because he was no longer alive (he said Boots on the ground) that she could not apply. They also mentioned that because he did not go to a VA hospital ( he went to Mayo Clinic because the condition was so rare they had a hard time identifying the condition).
From my limited research on the VA site. I think this guy is wrong. He served in the parameters of the Agent Orange area. His condition is covered under the Agent Orange diseases. Angiosarcoma is on his death certificate. They were married while he served and when he died. She has no remarried. Please give me your opinion on if I should continue with this.

Jim's Reply:

"She went today..."   Where did she go? Who did she talk to? She's allowed to apply for a benefit at any time. That doesn't mean she'll be awarded a benefit but she can apply. You can help her do this on-line and nobody else needs to be involved.  f there are any bumps along the way, talk with a veterans law attorney for free here .  Talk with any attorney there, some have probate experience too.