I'm happy that you have asked me to assist you with your child and hope that you can benefit from my many years of helping parents like you.
The temperature is not really anything to worry about as fever is not harmful at all, even to 104-105. Since it is just the first day of fever and he has no other symptoms you don't need to do anything other than just giving him tylenol and ibuprofen. Since he is drinking well he is not going to get dehydrated so just watch him for another day and see if any other symptoms occur.
We are seeing lots of roseola right now where kids his age have fever to 103 or more for 2-3 days and then the fever breaks and a rash appears. These viruses are all harmless so you are safe to just watch him for now.
I see you are offline still so I'll exit chat but am available for any questions you might have.
Since you've not accepted/rated my answer I can only assume I did not meet your expectations. Please let me know if there is anything else I can do for you. Thanks and regardless I hope your child is doing well.
We ended up taking him to the ER because we could not get the temp under control and he was clearly in distress. The pediatrician there mirrored your opinion in that it was a virus and had to run its course. He has already had roseola but they said that his throat was red. Three days later now and the temp has come down and his disposition is much better.
Appreciate the help!