You are free to contact him! I'm not sure he is not willing to share. Sharing code to the public in research depends on several factors, it can get open source

You are free to contact him! I'm not sure he is not willing to share. Sharing code to the public in research depends on several factors, it can get open sourced when the thesis is done, it may depends on who is paying the research (eg: some industrial PhD are not public), long term plan exist to publish the code but there are only 24h a day and a whole lot of work to do, the author/uni may want to make a business after the thesis, and a lot of other parametres. It gets even worse when the code is used in medical applications as a validation process with all the relevant authorities has to be done. This can take a lot of time and freeze the code in the waiting for a certification. Also sharing code between researchers is very usual, it doesn't mean the code has to go public. In this case I think it is part because the original matlab code is patented, research is ongoing and as it is research code it is not necessarily public ready. It doesn't mean he will never release it. If you desperately need it, the matlab code is available, and has the same functionality, you are free to adapt it or use it directly (for research purposes). I must say I don't like that the original code is patented, but I see hundreds of reasons why the authors patented it even if I don't particularly agree :)