There are several things that we can ask of a person who claims enlightenment or spiritual awakening, things that they must experience:
What is your experience of this present moment? Are you perfect, and if so how not? Did you surrender and let go to awaken, and how? How do you know if someone else is awakened?
If you really want to put forth a challenge them, ask: what is love? What is consciousness? What is awareness? Are more people awakening now, and how do you know that? Do you have any fears and if so what are they? What are the main obstacles we must overcome to awaken?
When they describe their experience of enlightenment, is it genuine or just a memory? Nobody will have the same answer to any of these, and if they do consider if it is a cookie-cutter response. If they say "I don't know" is it because they have never made the effort to contemplate it out?
Most of all use your intuition and heart to guide you, and stay open-minded. Later, the answer should come to you, and help you in your own spiritual development. I have asked these questions to many teachers and seekers, many times. I believe the biggest failure in teachers is when they undergo a profound but temporary experience of awakening and pass on only the memory of it.
There are actually many more questions and ways to tell if an enlightenment claim is false. I stand by as always to be proven wrong, or to hear and learn more about anyone's thoughts and experiences. May the heart guide your wisdom.