Obituaries are a notoriously secondary source. As such, they can easily contain errors or omissions. Sometimes this is done intentionally, sometimes accidentally. Regardless of the reason, care must be taken.
The spouse might not be the parent of all the children listed. Sometimes children and step-children are intermingled. The same thing with grandchildren.
Marriages may be omitted--especially if they produced no children or if there were "issues."
An uncle of mine died a few years ago. He and his first wife divorced. She was not mentioned in the obituary. Nor were their three children. His second wife was mentioned as were their three daughters. Their son was not included in the obituary because he and his mother were on the "outs" at the time of the father's death.
Obituaries are clues. Treat them as such. If you are looking for gospel truth, try the bible. You might even find a few old obituaries tucked in there as well.