If he had invested for such a long period, his return should have been more than 6% annually. It is likely that his fund was badly managed, e.g. in speculative investments, or had high charges that are taken away from his return.
There is a segment of the fund management industry that behaved unethically. The fund manager takes away big fees, but were not able to achieve a good return to the investors. The fees take away a large part of the return and gave a poor net return to the investor.
Many life insurance products also offer a poor return, of 3% annually or less. Considering that inflation must have been around this level, the poor return is just able to match inflation. For investors who took our their money earlier, the high front end fees led to a big loss of their savings.
Be careful of bad financial products. Many financial products fall in this category!