Hi and welcome! You have come to the right place for info and support.
I have never heard of a Dr. Fullum, or any other surgeon in DC, doing a DS, let alone a revision of RNY to DS. RNY to DS is a complex and high risk operation that involves a complete undoing of your old RNY, restoring all the original anatomy (meaning sewing the pouch and blind stomach back together and sewing the divided small intestine back together) and THEN doing the sleeve gastrectomy and bowel rearrangement of the DS. There are only a handful of very experienced DS surgeons who are willing to take on this operation. The risks are real and recovery sometimes takes months, even in the best of hands. Dr. Fullum may be a fine RNY surgeon, but the DS is a very different operation, and then the added difficulty of RNY to DS revision puts this on an entirely different level. Even if he has decided to add the DS to his practice - which would be great as we always welcome new DS surgeons - you are not the right patient for him to begin with.
I am not saying all this to talk you out of revision, but rather to explain that having this done by someone who doesn't do the DS and revisions of other operations to the DS on a regular basis would be a big mistake. You need to get yourself to one of the experienced DS revision surgeons. any travel or other inconvenience involved is well worth the effort. Given your location, the closest I know of is Dr. Greenbaum in NJ, who does these revisions on a selective basis, depending on how the original RNY was done. He has an excellent reputation and is accustomed to working with patients from out of town.