To clear up some of the confusion you experienced, this pension is available to the veteran and the
"surviving spouse". If your mom remarried, then she is no longer a surviving spouse, she is now the wife of someone else. This question is one of the FAQ's on the home page of the site.
http://veteranaid.org/faq/index.php?action=artikel&cat=3&id=14&artlang=en The exception would be if the 2nd marriage ended before November 1, 1990.
If her second husband was indeed a WWII veteran, then as long as they were legally married at the time of his death, she would be eligible based on his service.