Hmm... The fact that he didn't seem interested in eating the shed and had a hard time with it is of some concern. First thing to consider, the temperature on the warm side should be raised to be closer to 90F in the day, dropping to mid 80s at night. That would help with digestion.
The no shed and odd behavior... (though, admittedly the behavior itself isn't troublesome, but I'll go with your daughter's gut feeling that something is wrong, geckos are easy to bond with that way.) I think the best thing right now is to monitor the gecko and make sure it poos on his regular schedule. The only thing I can think of off hand that could cause all the symptoms might be an impaction from the sand, too much food at once (as the other poster suggested, I haven't seen this personally), or low temps... all of these can lead to higher chances of impaction in an otherwise healthy gecko because their gastrointestinal track isn't moving correctly. If the gecko refuses food for two consecutive feedings on his normal schedule and you don't see any new "deposits" take him to the vet. Sometimes all that is needed is a visual inspection under a bright light and they will see the backup.
If you notice anything else or have any concerns at all, please post more. We'll do our best, your daughter caught this very early, there is chance it will pass on its own, so honestly it is a wait and see. Good job for not posting our normal sights of "my gecko hasn't eaten in 4 weeks and lost all the tail fat, is something wrong?" Take care. Keep watching him. Warm him up and maybe everything will take its course, but keep the vet number handy. We'll be pulling for you.
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0.1 Albino Leo Gecko
0.1 Crested Gecko
1.0 Dear Boyfriend
Departed: Harvey and Spock