iMac Boot Problems

My parent’s new iMac won’t boot. I can’t get any of the dozen startup key strokes to work including “T” to get to target disk mode to pull off their data. My dad has booted it as late as Wednesday but it locks up after 10 minutes. Once it is shut down I meet a a gray screen without the Apple logo. 

I believe it is a hardware issue but I’m holding out for someone out there to have a final suggestion. Help me!

I have a backup of their data so I don’t feel too bad. The worst feeling is pushing them to get a Mac for years and their first one failing them. My plan is to take it back to Nashville, get it fixed, and bring it back up in two weeks.