How can I withdraw the ICO funds into fiat currency? through the bank? how is this possible?
It will hard cap until it reaches the expected value buddy. It need to reach the softcap that is actual successful for the ICO token sale period. If you want to get the tokens to fiat currency. First you need to have the token sale to the ERC20 token wallet like MEW.
Then you should have the ethereum on the concern wallet to transfer the tokens to exchange. If you want transfer to the exchange first you have search where these tokens has been listed on the exchange with the help of coinmarketcap.
If you have to doubt that token may dump in future. Try to sell the tokens when the time it launched to the market.