Your daughter's chameleon unfortunately doesn't look well at all. I don't like the way it's holding its nose up and how it looks trying to hang onto the plant/branches.
You said..."My daughter bought a baby veiled chameleon just over a month ago, maybe 2-3 months old. No idea of the sex"....look at he heels...if there is a tarsal spur it's a make if not it's a female...
https://www.adcham.com/html/husbandry/glossary/tarsalspur.html
You said..."It hasn’t eaten in a couple days and today it isn’t opening it’s eyes very much. She is providing 2-3 small crickets daily, dusted with multivitamin and calcium with D3"... A healthy one should be eating more than a dozen of the appropriate size crickets every day...lightly dusted with phos free calcium powder just before feeding them to the chameleon. Other appropriate sized insects can be used as well.
Twice a month a phos free calcium/D3 powder should be used instead of the calcium powder and twice a month a vitamin powder with a prEformed (retinol) source of vitamin A should be used instead. I know this has been mentioned already.
The insects should be well fed/gut loaded properly. You've been given some info for this already.
Improper supplementing may be a part of the chameleon's problems.
You said..."Water in dish and she sprays/mists several times a day and humidity stays between 50-70 most of the time"...it's not recommended to use dishes of water because they can harbor germs.
You said ..."Temp is usually around 80. She turns off the up bulb at night, leaves the heat lamp on 24/7. She has a Thrive set up from Petsmart, and also bought the Cham from Petsmart"...there should be no heat on at night unless your room temperature goes down below 60F. There should be no light at night....that might be part of the problem for the way the chameleon is now. The UVB light should be the long linear tube light...Reptisun 5.0 or Arcadia.
Curly or short UVB lights don't provide the right amount of UVB.
White lights should be used for basking lights. Basking temperature should be 80F for a young veiled especially if it's a female.
You said..."I don’t know enough about them and online information is conflicting and confusing"... You will get good information here.
You need to act,fast to solve the problems or you're going to lose the chameleon sadly.