The Las Vegas man whose severed fingertip ended up in a cup of Wendy's chili gave his mangled digit to a co-worker to settle a $50 debt -- but had no idea it would be used in an alleged scheme to swindle the fast-food chain, the man's mother said Tuesday. San Jose police have refused to name the man whose finger they believe ended up in the chili. But the man's mother, reached by The Chronicle on Tuesday, said the finger belonged to her 36-year-old son, Brian Paul Rossiter of Las Vegas. "My son is the victim in this,'' Rossiter's...