I'm not sure if this will find you almost 7 years later but I am a descendent of Thomas' brother Nicholas (he's my 3rd great grandfather). I have Nicholas' obituary which states that their parents both died of cholera in 1850. And I just discovered you can view it online here: http://wiclarkcountyhistory.org/0data/9/9939.htm
Do you have more information on what happened to Thomas after they died? And how he came to end up in Colorado? As you can see from the obituary, Nicholas went to live with a Nicholas Thomas, and after a stint in CA/OR returned to the Dodgeville area and settled down.