1999 gmc yukon, not running. Help

I have a 1999 GMC Yukon, it belonged to my grandmother, she passed and grandfather didnt want to sell it so it has been parked at my house for roughly a year.
It had a new battery before it stopped being used, my grandmother never sped or abused the vehicle and always kept it in good condition, besides the ac which stopped working shortly before it was parked.
Also she was the only owner and driver. And maybe about 6 or 7 months ago i took it for a drive, everything ran just fine. Until today i decided to try and turn it on, but the battery is obviously dead, and the car makes absolutely no sound when the key was turned.. but under the hood everything looks fine and tooken care of except for the obvious all fluids that will replaced or filled.. and i am very determined to get this suv running again. But where should i start?
ANY STATEMENTS WILL HELP.. the car does not make a sound, the battery will definitely be jumped as soon as possible. BUT WHAT ELSE could be the FIRST MAJOR PROBLEMS to get it running???

Probably dead battery. Jump start it and post back.

Put a battery charger on it. I have a B-I-L with a 99 yukon- 220k miles- other concerns are--

Intake manifold leak will eventually happen

A/C compressor case halves will leak- yours has already- look for greasy build-up on compressor body. Rear a/c lines will leak if so equipped.

4wd will be intermittent

Inside door handles that are often used will break or not open the door- plastic bushings wear- need replaced or pull rod bent to take up slack- I've done a bunch of these.

Defrost door actuator rod will pop off above gas pedal, hand down- cause mode door issues.

all that comes to mind for now.