Different input box width in a multiple short text question

Hello!
I would like to create a "multiple choice with comments" question with a different input box width for the last subquestion. The question should look like this :

What illness did you have in the past 5 years? Write how many time.
*cancer ____
*Fever ____
*Flu ____
*Other illness (explain) _______________________________________

I want the line to be longer so the participants can write a few things if they need to. Also, I already tried to put the option "other", but I don't like it because it shows 2 text inputs and there's no checkbox like all the other subquestions...

Thanks in advance!