If he earns profit from it, then he is an investor since anything that you put money on and expect a return on is already an investment, but if he just uses it like we use cash, receives it, and spends it, then he is a user of Bitcoin since he saw that Bitcoin is a good, anonymous, fast transaction, and probably this is the payment method that his merchant is asking for, which is why he is using it. It is not only holding Bitcoin; there are a lot of types of investors in Bitcoin: traders, staking, holders, and others who accept it as a payment method and hold it for a long time for profit.
Man sometimes I don't blame governments for trying to crack down, when all you guys seem to just love complicating things.
When you earn profit from something, it means you sold something for more than what you bought it for. That is called capital gains. It can be shares, stocks, coins, even a house.
It has nothing on its own to do with investment, investment is to put in effort or money in the hopes of getting profit. Hopes, not guarantee.
You can have losses and it's still an investment.