I used the names you posted and looked for other public trees, and found the one I will link below. It has both Lillie and Lucy but not Hettie. A link (maybe another?) between Lillie and the Bowman's comes from her mother in law, who was a Bowman. Now, it's not uncommon for cousins and 2nd cousins to marry, so perhaps there is another genetic link as well (the tree does not list Lillie's parents or ancestors). The Bowman connection I found would not, of course, be a DNA connection. Interesting note is that Lillie, like Lucy and other Bowmans, is from Patrick County, Virginia. The likelihood of your father being born in Patrick County is pretty high. I would re-post this to Patrick County message board as well (but I think it's good to keep this one here, mods, since the other is a guess) and the Bowman message board too. Someone will be able to help you I think.
By the way, Lillie's profile on this other tree has her first and middle names reversed, but it's obviously the woman you are referring to.
Finally, I hope you are sending private messages to these tree holders, for they might be willing and able to help as well.http://person.ancestry.com/tree/11093765/person/6079445968/f...