75K with 2K Spend Business Gold (Targeted)

I received an offer via snail mail for the Amex Business Gold with 75k after $2k spend in 3 months with annual fee waived for the first year. One addressed to my wife and one addressed to my 19 yr old son who is away at school and has no current income. I immediately applied for my wife and received instant approval. Too good to pass up.

My question is does anyone have experience applying for business cards for your children/dependents? He is additional card holder on numerous accounts but has no real credit history of his own.

Comments/suggestions??