When considering long term decisions, you must include time-value-of-money in the analysis.
Explain what is meant by "Rate of Return." Why does a business owner need to understand rate of return. Your client has told you that he only cares about cash flow. As long as he can pay his bills and take out some capital form the business, he doesn't care about anything else.
Explain to him why rate of return is fundamental to any long term business decision and why he needs to understand the how to use the present value method when making long-term decisions.