hi still. i think it's really awesome that your brother cares so much for you. but a few things he said like that you're giving in to rsd or that it's not real and all in your head are not true. rsd has physical symptoms as well as constant pain which is proof that it is not all in our heads. i also think that personally if it were me i would get some information about what rsd is and how there is not cure for it and have your brother read it. i would also have him read about the various treatments to manage rsd pain one of which is medication which works for some people like me and occasionally has to be increased because of rsd spread for example.
then once he fully understands what rsd is and how it can be treated then maybe i would consider taking him to a dr appt with you. (this is jmo though). i would want to make sure he is calm at your dr appt and not mouthing off at the dr, because in my experience with drs throughout the almost five years i've had rsd, "they don't like when you mouth off at them" and it might compromise your relationship with your dr.
please know again this is jmo and the decision has to be yours. again i think its great your brother cares so much. but he has to maintain control not only to not tick off your dr but more importantly so as not to stress you out more because that will increase your rsd pain.
i hope that once he is well educated on the realities of rsd he can help you by being there for support when you see you dr for follow ups. i hope all goes well no matter what you decide for you and your brother