I have read a few books and enough articles in my life to form my own opinion...here is a long long list of comments and resources from people who worked with him and with his family:
http://www.findadeath.com/Deceased/c/bing/bing_crosby_by_kevin_hassell.htm
You choose to believe the worst, when ALL EVIDENCE points to the son lying thru his alcohol soaked brain. But believe as you wish.