Okay, sounds to me like your friend wants to totally prevent search engines while at the same time allowing most websites. In other words, no Google, no Bing, no Yahoo, no Baidu, no AOL, no Ask.com, and the list could go on and on.

If my understanding is right, then the best option to cover all bases would be to do as follows:

 1. Go to Settings 
 2. Tap *General*
 3. Tap on *Spotlight Search*
 4. Disable *Siri Suggestions*, *Suggestions in Search*, *Suggestions in Look Up*
 5. Exit Spotlight Search
 6. Exit General
 7. Tap on *Siri*
 8. Either disable Siri totally OR disable *Access on Lock Screen*
 9. Exit Siri
 10. Tap on *General*
 11. Tap on *Restrictions*
 12. Enter a restrictions passcode
 13. Swipe up until you see the list of ALLOWED CONTENT options
 14. Tap on *Websites*
 15. Tap on *Limit Adult Content*
 16. Tap on *Add a website...* under the NEVER ALLOW heading
 17. Enter google.com and tap Done
 18. Repeat step 17 for any other search engines he wants to restrict
 19. Exit Websites and return to the main Restrictions screen
 20. Swipe down to see the top of the screen
 21. Disable Siri & Dictation
 22. Exit Restrictions

Now, the above is total overkill, but should do what he wants. He can then go back and re-enable certain things if this is disabling more than he wanted.