Not sure what the ultimate definition of "bro" is, but all the DIKs are "bros". But Derek cares more about the mc than the rest, and Tommy cares less about the mc than the rest.
The question is: Is Derek a good bro? Weighing up the pros and cons of a friend like Derek is highly subjective.
Are you looking to have an insane time, the hell with the consequences? Derek is you man, just don't be surprised if you end up with a criminal record for misdemeanours!
You wanna be serious about shit, make sensible decision which result in a strong future? Avoid Derek like the plague.
Of course, you can take the middle ground. Enjoy his hijinks but know when to pull out (pulling out at the right time can definitely make all the difference
)