While I do agree that technical analysis play a big role in trading success but there are also other things we should put into partners like fundamental, learning stop loss, resistance, etc.
But I do have acquintances who are doing some trading without the use of technical analysis. They're just doing some buying low and selling high. Waiting for bitcoin and other coin to decrease in price and then buy again. They are just following the hype and go with the flow. Just as simple as that and they are still profiting.
I am sure that using this tactic in trading at some point your friend will sell their BTC and will no longer be able to buy them, because the price will increase greatly. And he will have to buy at a higher price than he sold earlier, or wait a long time for the price to return to the level when it will be profitable for him to buy this coin again.