It will be based on how well he manages himself before investing.
The investor has targeted and also the period of investment. Some are being long-term investors so that they will not mind enough with the decreased price.
Here, if an investor has been ready for the investment, he will be ready for the risks, including the loss of the money itself. That is why it is better to manage the funds to invest.
Being sad because of losing is normal, but never put yourself in bad condition often after losing. Keep moving on