I don't think so. It's not worded very well but I think he's saying two separate things. The FF at Rebecca's death bed is when Jack is teen/pre-teen, and the scenes of him as an adult are ten years after that.
ETA: So we know Kevin and Randall are silver-haired/graying. Tess is old enough to be a social worker. Kevin's kids are pre-teen. Jack is 'on the way' with someone, possibly Kate. Or since we now know that they also have another child, 'they' could be Jack and his sister (whose name escapes me). If they do adopt an older child, it's possible that she's old enough to be driving Jack to the house on her own. Beth is there, as well as Nicky and Toby. Still unaccounted for, Miguel, Annie, Deja, Kate, Kevin's baby mama(s).