iCloud won't sync Gmail contacts, it will only sync iCloud contacts. If he wants to use Gmail for contacts, he should add his Gmail account to his Mac too. If all of the contacts on his phone are not appearing on his Mac after doing this, then some of them must not belong to the Gmail account and would need to be added to his Gmail contacts.
If he wants to use iCloud to sync his Gmail contacts instead, he can copy all of his contacts to iCloud as follows:
- Go to Settings>iCloud on the phone, turn Contacts to Off, choose Delete from My iDevice when prompted (any iCloud contacts will still be in iCloud).
- Download the app My Contacts Backup. (If you have more than 500 contacts to transfer you will need the “Pro” version.) Use the app to back up the remaining contacts on your phone (from Gmail and any other non-iCloud accounts) as a vCard attachment to an email that you send to yourself. Confirm that you have received the email.
- Go to Settings>iCloud and turn Contacts back to On.
- Go to Settings>Mail,Contacts,Calendars>Default Account (in the Contacts section) and set this to iCloud.
- Go to Settings>Mail,Contacts,Calendars…tap Gmail and any other non-iCloud accounts and turn off contacts syncing with these accounts (otherwise you will see duplicate contacts on your device).
- Open the My Contacts Backup email and tap the attachment to import the contacts from the other accounts back to your device, and to iCloud.
