As HRFFW states above, we need more information in order to identify Konrad’s Danish offspring.
Consider the following:
How do you know the nationality of Konrad?
How do you know the year of birth for Konrad?
How sure are you about the year of immigration for Konrad and Petra?
Do you know if Conrad/Konrad had more christian names that could help identifying him (this would be common at that time)?
Where did Konrad and Petra marry (US or Denmark)?
Any children (year of birth and names)?
Where did they live (US state)?
Year (approx.) and place of death for Konrad?
It’s very important that you distinguish between what is documented, and what you may have found on various family trees on the Internet.
By the way the Danish Emigration Database ends with 1908, so the immigration will most likely have be found via US sources if 1910 is valid.