Please help me in this case study – Ethical issues in accounting

I had come across a case study, can you guys help me about it?

John, a young CPA and one of the audit team members for Moulberg Electrical Appliances Ltd, has developed very good insights into the company’s systems in the last 12 months and was asked by his partner, Chandler, to draft a report on the reliability of the internal control at Moulberg for review. The report is to be used as a part of a due diligence assurance engagement for Moulberg’s prospectus. Moulberg wants to be listed on the Australian Securities Exchange by next June.
In carrying out the review, John finds a number of matters that concern him. He notices that the controls over inventory requisitions are very poor, leading to numerous complaints from customers about delays and long deliveries, and cancellations. Moreover, the inventory records do not show the history or the values of the inventory, so that estimates were used to arrive at the year-end inventory. He also noticed the poor standard of the appliances with manufacturers warranties long expired.
John completes his report, with details of the poor internal controls for his partner’s review. However, his partner replaces his report with a very brief summary and a conclusion that the internal control systems are sound and reliable. John makes an appointment to see chandler, but is worried as to how he should approach him about Moulberg Electrical Appliances’ issues.
Required
Discuss the professional and ethical issues faced by John and provide an analysis which can help him deal with the matter with Chandler.