Apparently there was an episode where Roseanne says that Jerry is on a fishing boat in Alaska and that's it, lol.
The showrunner said that Andy might have been sacrificed to the 'dream period' where the timeline is questionable... even though Andy is born like a couple seasons before the lottery season. You could apply Pegg's explanation of the differences in the Kelvin Universe and treat Dan's death (or not death) as the point of temporal incursion where changes to the timeline can occur in both directions. Roseanne was so upset by it, it caused her to go back in her books and retroactively add in Andy.. or something. So then if we treat The Conners as a third timeline in which Dan did not die and they did not win the lottery, there would be no reason for this version of the story to include Andy persay, but in which is also a timeline where Jerry is born.
But the same showrunner also said that if Andy does exist then he would be at college. This leaves it open for them to add him in later on and make some joke of like, 'Where the hell have you been?' along the lines of their Becky jokes and the throwaway explanation that he's on a fishing boat. I'd bet if they found someone interesting to play Andy they would totally bring him in for that.