My son had axenfeld rieger as well as my husband. We didn't know my husband had axenfeld rieger untill our son was born. My husband only has a very mild eye malformation, his pupil is not exactly in te middle of his eye.
My son is 17 months old. Het has small tear-shaped pupils witch are not in the middle of his eyes. The preasure in his eyes and his sight are okay at this moment. He also has a heartproblem, a open 'ductus of botalli'. He has to be operated on this problem when he is older.
Our doctor told us that it's not likely he develops other problems. He is, just like your grandson, developing on target. But we stay under control with the pediatrician until he is a grown up. The eye specialist will check his eyesight and eyepreasure every 6 months.
Hopefully your grandson is doing okay! I hope you understand everything I rode, English is not my first language, so it's difficult to ride in English.