Congratulations on your brother for making the right decision at the right time. Surely, Bitcoin can give you a solid ROI but as always there are risks involved...as Bitcoin is very volatile digital asset meaning it can go up and down anytime and even for no reason at all. Bitcoin is known to an investors' haven as there is a big potential to make a considerable profit here...but you must act when it is good to act and always listen to the market and maybe even listen to your gut. Anyway, holding on to BTC with the idea of 2024 being a bull year due to its halving and the possibility of ETF approval can prove to be the best decision to do. Note: this is just my opinion.