My storage is 128 gb. Why my icloud is 5 gb?

Your iPhone device storage is fixed at 128 GB.

iCloud storage which is associated with each Apple ID - can be upgraded from the free 5 GB to the monthly billed 50 GB, 200 GB or 2 TB.

To know more about: iCloud https://www.apple.com/icloud/

and iPhone storage: How to check the storage on your iPhone, iPad, and iPod touch - Apple Support

Your friend is very lucky ... if it is a free upgrade to 50GB.

Most probably, he has not yet been billed, or the amount has been deducted and he has not realized it.

50 GB costs $0.99 per month.

Ask your friend to check: See your purchase history for the App Store or iTunes Store - Apple Support

Because that is the default, free iCloud storage capacity. Higher cloud storage can be rented if required.

I don't like to use the actual iPhone's storage. I like to keep all of my data stored in iCloud, because if my old Apple device breaks, and I have to get a new one, I don't want to have to do all of the verification on the old Apple device. I have been there before. My iPhone 5c broke, and I got the iPhone 6. The screen on the iPhone 5c wasn't responding to touch, and the issue was that I saved all photos to the iPhone instead of iCloud, and so I lost all of my old stuff. I know I could've transferred it by plugging the iPhone 5c into my iMac, but for some reason I had to enter information on the iPhone, which I couldn't do. So I really think Apple should increase the free storage from 5gb to... let's say, 10gb?