Spirit Airlines is accused of abandoning an “unaccompanied and disoriented” senior citizen with dementia at a Texas airport, after which the man wandered onto a highway and was fatally struck by oncoming traffic, according to a federal lawsuit reviewed by The Independent . In their complaint, Marcos Humberto Vindel Osorio’s surviving relatives claim they informed Spirit upon check-in about the 75-year-old’s cognitive issues, and said he would require assistance deplaning and navigating through the terminal upon his flight’s arrival in Houston. “Spirit’s agent confirmed that assistance would be provided,” the complaint contends. However, it goes on, “Spirit provided none.” When Osorio never appeared in the arrivals area at George Bush Intercontinental Airport , family and friends waiting for him became increasingly concerned and called the police, according to the complaint.…