There is actually one spot I found online which claimed Madelyn’s ashes were interred with Stanley’s at Punchbowl and that was even after the public spectacle of the “ocean dump” and the horrible display of Michelle jumping up into his arms with her legs wrapped around his waist like all their problems were now over. I couldn’t believe it when I saw that picture and it has probably been removed from the internet by now but the mention of Madelyn’s ashes being placed with her husband are still around, IIRC they were part of some tourism website.
Here is the link as per your request
aand here is the direct quote which was done after the infamous ashes dump!
PUNCHBOWL CRATER The National Memorial Cemetery of the Pacific is the resting place for over 38,000 casualties from WWII, the Korean and Vietnam Wars. A shrine commemorates the missing-in-action. The rim of this crater provides an incredible view of the city of Honolulu. This is the final resting place of Barack Obama’s beloved grandparents, Stanley and Madelyn Dunham.