I’m not familiar with this family but some more details such as DOB, Place of Birth, DOD, etc. would be helpful.
I did a quick search on Ancestry for the name Ernst Alves in Comal Co. and found several listings including a WWI draft registration card. If you are not a subscriber to Ancestry, try your local library. Some libraries have a free subscription to Ancestry that is available only in the library.
Looking at the card, his DOB is listed as 19 Jan 1898 and his nearest relative is listed as “Paula N???day”. Is it possible the Paula remarried after Ernst Sr. died??
There is also a 1900 census in Comal Co., Texas listing Ernst Alves born in Jan 1898 living with the Lorette Kloepper family. Below is the listing of the HH members:
Lorette Kloepper 60
Johanne Kloepper 39
Albert Kloepper 28
Paula Kloepper 24
Emma Kloepper 17
Ernst Alves 2
Hope this little bit helps in your search.