When the Handle gets stuck I can't get out from the Inside and I have to reach out the window and push it in just to get out. I usually remember to push it in when I get in, but my dad doesn't.

 

I had that happen to me.
You can either disassemble the door panel, and clean everything and check if anything is broken, or you can do like I did, and spray alot of WD40 from inside and outside. and use the handle multiple times after doing that, so the WD40 really gets into all the needed parts.
This last one fixed mine, without the need to remove the panel, I just sprayed from outside, and I took off the little panel from the inside handle, and sprayed from there too.

this was the thread I opened at the time: https://www.hummerforums.com/forum/h...en-used-24448/