Hi. I am not sure if it goes by weight maybe google that phrase. Did you ask the doc? As for shoe size and I am not saying to not look into it. Better safe then sorry and at least the doc is thinking like that too and looking deeper. Anyhow I have went up one size this year. I also know that thee feel too tight but even the next size does too. I often wonder if it is just that my feet feel so uncomfortable. Again I am not saying this is true of your husband but just a thought.Let us know what happens with the results.