couple and son's B2 visas denied

May I post your experience on the internet? Let someone guggest us.

It is really pity. My husband and son were denied when applying for B2 visa together. The Q&A is as below:
1)why do you go to us?
To visit my wife and travel
2)Show me the invitation letter
Forward my school letter to another officer and that one shaked his head after reading.
3)Give me your passport
My husband cannot afford the old passport with US business visa because it belonged to the company and then VO check the computer for 10 minutes.
4) Sorry......
We have prepared enough documents, but the VO only watch the 156 form.

1)The invitation letter was issued in January this year, is that not good?

2)VO seemed not to find out my husband's record of US business visa 6 years before via the computer system. We cannot believe that at all.Is it strange?

3)How many days later can they apply again? Can they apply for F2 separately, my husband first, and then my son?

Thank you for help.