Hope he makes it, please make sure he is seen by a reptile vet , this is very urgent , a little hatchling has zero reserves .
If the hatchling taking any liquid when you drip a few drops of water on his snout ?
if he is this will make it easier to get him to take liquid food substitutes like those I list below , he'll like the taste of the liquid food substitutes and will lick them off his snout or side lips of his own accord , and you wont need to resort to forced feeding or even using a feeding / crop needle to get food into his stomach.
If the local pet shop is still open buy a 1 ml syringe and a nozzle , and a bottle of VetaFarm HerpaBoost or VetaFarm Crittacare Reptile OR EQUIVALENT ( Oxbow Carnivore Critical Care is very good ).
Info :
https://vetafarm.com.au/product/herpaboost/
https://www.vetsupply.com.au/supplements/reptiles/vetafarm-reptile-crittacare/p2060.aspx
https://www.oxbowanimalhealth.com/our-products/professional-line/carnivore-care
See this for required kit and tips for giving liquid food substitutes and oral meds to reptiles :
viewtopic.php?f=45&t=232687
These are very potent vitamin and protein fortified liquid food substitutes that are very good , I've used the VETAFARM products with rescued lizards who looked like were very close to being beyond saving who recovered and made almost miraculous comebacks. My latest Fluffy the water skink has become a house pet and has thrived and become ubertame and friendly.
You will need to weigh the dragon , as the daily dosage is determined by body mass - several small feeds is going to be much easier to get into the dragon using a syringe (by mouth) and will not be as hard for it's potentially compromised kidneys to handle.
Have you tried hand feeding him ?
see this
viewtopic.php?f=18&t=235583
A technique I use with crickets as a feeder is as follows :
1) select a few gut loaded dusted crickets, place in a small tub with a lid
2) take 2 out , squash their heads , this disables them , take hold of the cricket by the longest (jumping legs) and gently place the squashed head-end against the lips of the dragon (side of mouth near nostrils (the smell is get starter) , often a hungry lizard will take the cricket (watch out finger tips) , BUT it may need some extra coaxing
3) if it needs extra coaxing , take hold of each of the two long hopping legs, twist , the whole leg (foot + shin + thigh) should come off ( I refer these as cricket drumsticks). I then take one of the drumsticks , and gently force the knee or the thickest end inbetween the lips of the lizard (front side of lips) the taste should be enough for the lizard to take it and start chewing the drumstick ,
4) then - this will take good timing - I position the rest of the cricket (squashed head first against the lizard's lips while it's chewing the drumstick (watch out fingers)
A technique I used when using BSFL is as follows:
1) select some large while or black wriggling BSFL , place in a small sauce dipping dish.
2) take a worm and hold it using your fingers so the head is facing the lizard
3) gently press the pointly (but soft) head of the worm between the middle to back side lips of the lizard, once the lizard bites the worm you will hear an audible pop, and the lizard should do the rest.
Another worm technique I use with BSFL is as follows:
See 1 above
2) take a few worms and snip off the pointly heads (only need to take off 1mm to 2mm)
3) squeeze out some of the worm innards and do 3 above.
Another method for worms I use is as follows :
See 1 and 2 above.
3) squeeze out all the worm meat onto your finger
4) deposit the meat on the lips of the lizard near it's snout, the lizard will lick the nutritious worm meat off and eat it , can be very tedious so I usually do 4 to 6 BSFL at a time so the lizard get a nice big lump of worm meat to eat each time.
5) discard the husks , unlikely the lizard will eat these.