Anyone can invest in Bitcoin. Your friend. Your enemy. Your whatever. However, you must advice them to learn about the basics of Bitcoin and cryptocurrency first. Investing in Bitcoin without having a basic knowledge of Bitcoin or not knowing what you're doing is a recipe for failure. You don't just follow the band because everyone is in the band. Invest in bitcoin only after study and research.
I do not think that there is any rocket science in bitcoin investment, a person can learn about it in few hours, but becoming a good trader specially for becoming a day trader he need to get some experience first, because trading require some good experience and trading skill, without good trading skill and experience trading can be consider as more risky.