My son is 14 year old.a week ago, he took a hand x-ray and was told that growth plates were 99.4% closed.he is 5'3 in. can he grow 3 inches in anyway.

Don't expect it: Three inches is a bit much, half an inch is a maybe and nothing is a possibility. Most males close their growth centers by 16-17 so this suggests early closure. Most read outs give a "bone age" not a percentage, but I interpret the wording to suggest a bone age of 17. If he grow more than 2 inches in the past year he may grow more, but if less than an inch I think he's near done.