is this the better way to come to US early?

Here is the situation.

My sister's family is in the process of GC with family A5 (US citizen allied for married siblings), their priority date was 2001.7

Now my sister was appealed by some intermition companies claming they can help high school student to apply visa to entry US community colledges without taking Tofel or any other tests for two years, then if the student can survive, they can help student to apply US colleages. I know this is definitely a frank lie, these two years comminity colleadge is just ESL, however my sister thought this might be the better chance which can make my nephew (16 year old, and not that good in acedemic at all) enter US early, rahter than wait till who knows when till they get their GC.

 

My questions are:

1. If he comes, would this defeated his GC application?

2. If not, what is the procedure for him to get his GC when their family status is about hte time to be changed? could my nephew adjust his status in US without going back to China?

3. Of cause, I would like to hear some saying from you all about whether this is a good idea or bad?

 

thank you all very much,