I wonder if anyone has ever checked FMD’s gravesite...or was he “buried at sea” too, like OBL? It would be interesting to learn if any remnant of his DNA is still in available for testing.
Why would you need Frank’s DNA? Ask his son Mark. He would be happy to clear his father’s name, but what DNA are you going to compare it with?
Speaking generally I don’t personally place much faith in trying to use “who someone resembles facially” to speculate as to parentage.
However, if anyone is going to insist on going down that route, then they ought to stop and also consider the people still alive who are connected to Obama. The person in that group who has by far the best and most obvious facial resemblance to Obama is Mark Ndesanjo, his purported half brother.
Seeing as there is precious little doubt that Obama Sr was the father of Mark Ndesanjo, that would make it long odds-on favourite that Obama Sr is also the father of Obama.