Dying tree help! hopefully not dead already

[a0c8c]

My parents bought a new tree for the front for the second year in the row. They have to comply with the HOA's rule of two tree minimum in the front yard(which isn't bad at all). Last year they got in planted in May or June and of course, the tree didn't make it. Tried telling them it was way too late, but they didn't listen. So this year they got it earlier, but still not until late March, early April when we were already in the high 80's. Tree seemed to do fine, wilted a little at first but then sprung back and has looked healthy ever since, up until Monday. From Monday to Tuesday, the leaves on the entire tree have turned brown and are sagging completely. Tree looks pretty much dead. Saturday it rained some, but not for very long, and it stayed extremely humid all day. Sunday was kinda humid, but didn't rain. Monday it rained a little during the day, and stormed with a fury around 6pm. It's been raining off and on since. The tree was planted with a foot of new soil full of compost around it, and 3 feet below it, giving it the best chance and was planted by professionals, so I know it was planted well. It's been watered every Sunday by my parents irrigation system, and has two nozzles that spray directly towards the tree. I will note, the irrigation system was put in after the tree, but was done in mid May.

We have not idea what happened to the tree. It look healthy Saturday when we had family over, but now is looking dead. Any ideas?

Here's an album of some pictures of it(and two rose shots I accidentally added in as well)
https://imgur.com/a/d4Zh7

[Dillbert]

looks pretty grim.

try a drizzle from a hose at the base - about one hour minimum - every other day or so in the heat. obviously the sprinkler system is not putting on enough water to penetrate into its root zone.

it may or may not make it.

[Smallgardener]

I always scratch the tree to see if the stems have died. If it is green then there is still life in it. I had a sycamore loose its leaves last year at least once maybe twice. same situation. Planted late and it was 8 ft tall, and very root bound in the pot. It is still alive but still loosing leavs this year. An 8 ft tall tree that is potted an then stuck in the ground has a root ball adiquate for a 2 ft tall tree. That tree needs lots of water to keep it alive. I already have a sycamore to replace the one that is not going to turn out well. The new one is in a bucket, came as a bare root twig and has grown 12" already since May. It will catch the one in my yard in size by next year I bet. Good luck and keep an eye on it.