I would not accept a job without a clear understanding of job description, compensation, work schedule, etc. If they can't answer all those questions, I would pass. Or I would give a verbal acceptance and request further written communication/documentation of job, requirements, benefits, etc. How soon would he have to start?
Yup - add me to the concerned pile. I interviewed for a job once where it wasn't that they wanted an answer "today" but they wanted me to start in less than a week because it would require flying to CA for training. Even though they knew this schedule MONTHS before, they literally waited to the week of to final interview me and offer me the job.
There was more to the story, but this was one of a few red flags and I turned the job down. I could tell they were pissed- they needed someone. But oh well!
If they aren't answering every single question in full and are insisting on some crazy arbitrary shot clock to accept I would walk away. Unless it's his dream company or he needs comp.