if you arent feeding him directly by the syringe, then it should avoid aspiration.
aspiration is when food/fluid gets into the lungs instead of the stomach. it can cause sudden death, or it can cause pneumonia.
ideal temperature of formula should be 104-106 F to prevent problems. do not microwave formula, heat it up by putting it into a glass cup and put the glass cup into boiling water to heat it evenly until it reaches that temperature. you dont want it too cold, because it can cause slow crop, which can cause sour crop. you dont want it too hot, because you can cause crop burn.
handfeeding is scary. since the petstore unfortunately isnt going to take him back temporarily, do you have any breeders or even the petstore to show you how to do it properly?
also, can you post photos? it would be good for us to be able to help you, so we can help make sure you raise this baby good and healthy.
it will be very important to make sure his weight is healthy. you should check the keelbone. these collages should be able to help you:
this shows what an underweight bird looks like
this shows normal weight:
and overweight:
knowing if your baby is a good weight is important to know if he is getting enough to eat as well. if he is losing weight, he might not be eating enough, or if he seems to be eating, but is skinny, there could be something wrong. knowing what to look for with weights in birds is very important because it can tell you if something is wrong sooner.
i dont know how much lori babies need to eat, so i cant help you there. i was just concerned about this sounding like an unweaned baby. but dont worry, this forum will be glad to help you and there's many experienced breeders here who should be able to give you good advice.