miscommunication

I think the attorney means H1B visa last 3 years, which is true, not applying it takes 3 years. So could be the employer misunderstood the attorney

For this kind of employer, they are totally in dark about H1B, then you need to collect information and make sure you are knowledgable about the issue

Ask them to hire an immigration attorney, then the attorney will tell them what to do and tell you what to prepare. But like I said, you yourself need to do a little bit home work.