Vikas, sorry to say "to the best of my knowledge" Tableau column width controls are not like Excel, and will need to be manually sized, on all 12 sheets. And yes changing one can/will ripple the others.
The other thing you'll probably discover is that the default number of columns allowed is 6. If you exceed this limit Tableau starts combining your columns. You can increase the number of columns allowed by going here:
Clicking 'Advance' takes you to this box:
You can have up to 16 columns. Hope this helps.