I remember reading that he wanted to retire back in 2010...he had to do all of these shytty movies because he knew his thyroid was worsening his health. Really sucks. My boy has the same thing Jet Li has now too, he's only 29.
A friend of mines dad dealt with that same thyroid situation. except it wasn't him it was his old lady. She's in her 40s and when it started to act up it sapped her of all her energy, had her looking like a shell of herself.
They went to see some different doctors and they put her on medication. There was a slight improvement but nothing concrete. my friends dad pretty much had her bush the medication and just switched up her diet, straight fruits every night. Honeydew, Kiwi, Grapes, Cantelope, Pineapple, Oranges, Bananas, Mangos, etc.. some combination of that every morning and night for about 2-3 months straight.
Right now she's doing better than before the Thyroid first started to act up, best she's felt in years. Diet is a major key in so many situations, tell your boy to jump on those fruits and take it seriously.