My question would be: does he obviously hiding a lot of earnings from me in day trading, that he would do from Mars to December? Or is he legit to say he is just waiting all this time the good time to sell BTC when it will be a good time(with a new laptop just for crypto that he bought, not a expensive one, but anyway)
I can't answer your question and provide an absolute answer for it but I can just speculate on to the existence of the funds you let him borrowed.
First things first, profiting in day trading is relatively difficult. As for newbies, there has been study published that around 97% of newbie day traders lose their money in the process and the remaining 3% earn as much as a bank teller. Though I am giving the benefit of the doubt to your friend (assuming that he is an expert on this field), then he probably made some profit out of the funds you provided.
Another thing, if your friend tells you that he's waiting 'until the price of BTC rises' can have multiple interpretations. The best course of action to do here is to ask for actual receipts and pictures of your fund.