My eleven month old had a fever of 104.0 fh. Was told didn't need to take him to ER unless its 105.0 fh. Is this true?

Please have him seen. With a temperature like that, i'd recommend having him seen today. Given his age, it's a good idea to make sure it's not a bacterial infection. I hope he feels better soon!
Depends. I would try treating with appropriate dose of tylenol (acetaminophen) and tepid bath. If the fever does not come down within 30-60 minutes or if the child is signficantly uncomfortable i would recommend you take them on in to get checked out. If the fever is controlled you should definitely take the child to the doctor in the morning to find the cause of the fever.
Not really. You don't need a thermometer or set reading to tell you when to go in. If a fever does not vary over 8 hrs, if the kid isn't taking enough fluids to pee every 6 hrs, if the kid just spooks you; it's time to go in. I've had giggling 2 yo run faster than me with a temp of 105 and some with no fever at all that I hospitalized for days. It's better to do what your gut tells you.