As dumb as it sounds it can happen to anyone, especially in a situation such as his where he's recently suffered the loss of his wife.
When I first started going to strip clubs I met a stripper who fooled me into believing she wanted a relationship with me and who took me for everything I had.
Fortunately for me I was a starving university student at the time and "everything I had" was about $600 or so--a couple of dates, like literally two, and I was broke and she was gone. I had to borrow rent money from mom and lacked funds for beer for a few weeks, but I feel fortunate in having learned that lesson at that point in my life.
Now I'm aware of the games people play, and of my own limitations as a human male, and I cut off relationships with sex workers of any kind if there is any hint of attachment by EITHER side. I had to cut off a mistress who was starting to get a little clingy.