Mark Grayson is not a character from the television show “Dallas.” The show, which aired from 1978 to 1991, followed the wealthy Ewing family and did not feature a character by that name. It’s possible you might be confusing him with a different character or a different show.
In detail, “Dallas” was a prime-time soap opera that revolved around the Ewings, a Texas family known for their oil empire and cattle ranching. Key characters included J.R. Ewing, Bobby Ewing, Sue Ellen, and Pamela Barnes Ewing, among others. The show was famous for its dramatic twists, family feuds, and the infamous “Who shot J.R.?” storyline. If Mark Grayson is a character from another series or a later adaptation, additional context would be needed to provide an accurate description of what happened to him. However, within the original “Dallas” series, there is no record of a character by that name.