如果等主申请人的I-485 approval后，小孩过了21岁，还能file I-824？现在小孩还不到21，这样一起提交是否更好？问题太多，太谢谢了！
-The information you provided is very confusing. A couple of days ago, you post this "8老师好! 朋友在美，妻子儿子都在加拿大，去年他们以H4来美提交了AOS 485，然后返回加拿大。现在需要过来做体检，但是儿子已经过了21，网上写H4只能给spouse or child under the age of 21，这是否意味着他儿子不能拿到H4了？" Now you say: "现在小孩还不到21".
If the child is still less than 21, I suggest that the child ahd better enter US using H4 visa to enter US and then, do the figerpringting (if the child filed I-485 already) or file the I-485 (if teh child does not file I-485 yet).
If the child is > 21, the parent had better file I-824 now ( as soon as possible) for the child using the Child Status Protection Act benefits. Otherwise, his child will be age-out and thus, the child will not be qualifed for immigration as his derivative. The child and spouse do not need to have H4 status because they are not present in US.
Your friend had better consult an immigration lawyer in case there is trouble in the child's immigration because the information you provided is not complete and confusing.
