First of all, thank you for bringing our attention to this interesting composer. I had never heard about him before I read your post, but that's barely an indicator as I am taking my very first steps into exploring the Turkish
repretoir. Unfortunately, those among us who know more about this music have long disappeared from the forum. I hope they'll come back one day!
Now I found this wonderful article in both Turkish and English from Makam magazine about this composer, an interview with his grandson, who happens to be a baritone opera singer. I haven't read it yet but I think it will provide a sufficient answer to your question.
كود PHP:
https://books.google.co.uk/books?id=8wpjDwAAQBAJ&lpg=PA8&ots=f5ArddHqiq&dq=udi%20sedat%20oztoprak&pg=PA8#v=onepage&q&f=false