What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
Unfortunately, I didn't find a way to include more text boxes in radio buttons.
But you can check this widget: https://widgets.jotform.com/widget/user_contributed_radio_buttons
That will allow your users to input options by themselves, that will pretty much do the same thing as text-box (other option).
Let us know if that can work for you.