Well saying gambling somehow reduces the status of Bitcoin as an asset. However, borrowing cash into DCA is a kind of uncomfortable approach. Better and easy when it is based on as much as u can afford....
A proper self analysis will reveal his friend to be gamble minded which for sure unhealthy so far as DCA is concerned.
DCA can't be embarked on by borrowing, u invest as much as you can provide not otherwise since after all it is a long term investment approach...
Obviously, it wouldn't be very comfortable for someone who borrows money to invest, because they would ultimately have to repay the money to their friend according to the initial agreement. So, if it can be done with their own money, I think it would be much better than taking out a loan to do it recklessly, even if the chosen option is a good one, namely investing in Bitcoin. However, it would be better not to make loans the primary option in any activity, including trading and investing, if we are still concerned about our own comfort.