I can understand your concern for your husband.There is a common condition in Orthopaedics called as "Idiopathic arthritis". It means, there occurs joint swelling without any reason.It's due to this reason, all the results / tests are fully normal.
1) Who should he see now?
Orthopaedician is the correct person.Sports therapist can also help you.If your previous orthopaedician is not able to help you, then it's better to change the doctor.
2) What can I do to help him?
You need to help him with his physiotherapy, which include knee range of motion exercises, quadriceps and hamstring strengthening physio.These can be taught by the physiotherapist.
You said he is already wearing the braces.Is he wearing crape bandages/elasto-bandages also.As it helps a lot to keep the swelling under control.
Also please let me know as what medications he was on?
Waiting for you to answer my questions.
Thank you for getting back to me. My husband only is wearing the braces. For pain and swelling he just takes advil/motrin. His swelling is not bad when he wears his braces. He is concerned when he takes his braces off of a swelling/bump on the lower outside part of his knee cap. Coming down the stairs Saturday his knee gave way and he fell the last couple of steps down the stairs, this is worrying him. If I understand you correctly my husband knee could have arthritis in it and his x-ray and MRI would not show anything. Then how can they diagnose this condition? What questions should we ask the doctor? I look forward to your answers.
If your husband felt like the joint giving way, then you must discuss the same with the Orthopaedician.In these scenarios, i would suggest you to go for a Diagnostic Arthroscopy to rule out any other possibility.