It's a good idea to invest in bitcoins before buying clothes, but you should also remember to get stuff that makes you look good. Investing is good, and I also believe in not putting all my eggs in one basket. You can do different things that give you more in return.
About you helping your friend who used his money for Christmas clothes and shoes; it's not bad to get that stuff too. But if you have the money, I will advise you to help him out. But give what you can easily let go of.
It's not okay to judge people because we all have different priorities.
Always feel happy to know you're helping people, and the rewards will come back for you. You can also advise them on how to make more money without lavishing it on things.
Your post was so good that I had to merit it. Like you, I am also of the opinion that helping people especially when we are in a position to do so is a good thing. It would only be bad when you don't have enough for yourself but decide to be too selfless and give all out. And yes, everyone is entitled to their own decisions, especially the decisions of OP's friends to get clothes rather than invest. Since only they know why, I can't judge them.
~snipped
At all times, I recommend giving to others but only on the condition that you're in the position to do so. Because you can't give what you don't have. If you have but it must be left untouched then you have no other option than to deny your friend's request. True friendship won't be determined by the amount of money or loans you can give out to your friends anyway. Also, I don't think selling off your investment to give out a loan to your friend is a wise decision. Even with family, there is a limit as well.
This is just my 2 cents. After hearing people's opinions, you should give it some thoughts, decide and stand by your decision.