~snip~
What do you think about my advised to him?
Anyone can start to invest in Bitcoin at any amount, depending on the person if they want more profit in the next bull run then they should start with decent capital. As long as you use your money that you can afford to lose then any amount is acceptable, never invest in crypto if you're got in FOMO or just following your best friends since the risks here is really big and you should do some research too.
We can start to invest in Bitcoin with any amount of money we want and is something that don't have a fixed price for one to start. There are people that started investing in Bitcoin with $10 and with time there portfolio increase and more money was invested in the coin they like or want to get. Just like trading, we can trade with any amount that we want depending on the exchange that are supporting it. We need to know many things about where we tend to buy or keep our money.
We should also make sure we keep our money save from people that might want to take advantage of us.