I've looked at both websites, Brown Design: Interior Design Los Angeles and Jeff Lewis | Official Site and if I may, I'd like to offer my comments.
There is some overlap in which the same projects are shown on both sites. These are Valley Oak and some flips we've seen on the show.
Jeff's site appears to be projects that were done as flips rather than designs for clients. I say that because some of them are recognizable from the show but more than that, there is obvious re-use of the same exact pieces - furniture, lighting, artwork, rugs, etc. - in many of the homes.
I don't know if Jeff or Ryan designed the interiors for the flips, but they are very spartan (which is fine as a design style but only when done well) to the point of looking incomplete - lack of window treatments, lack of floor treatments, too-small rugs, too-few or too-small accessories, etc. There is a lot of repetition in the furniture placement. There's just a real sense of something lacking overall.
Ryan's designs, on the other hand, are quite good. They are actually more developed and polished versions of the designs on Jeff's website with more details, flourishes and attention to proportion, making them far more successful as designs.
So I'm not sure if Jeff has a solid body of design work to show to prospective clients, or if his portfolio is actually inferior to Ryan's. It just seems that if they could work together again they'd have the best of both worlds - Jeff's real estate & organizational expertise with Ryan's design skills.