Let's get the fact straight. There is no question about immigration petition in I-94 and I-94W.There is a significant likelihood he will be denied entry, or at the very least, given only a short stay as a result of having to answer 'yes' to the I-94 question of whether an immigrant petition has been submitted on his behalf.
Will he have any issues entering US for short visits (on B2) after I file I-130 petition for him ?