My 2.5 yr old son is having a fever for over 24 hrs as high as 104, what will I do? Should I take him to the hospital?

Yes. Lots of possibilities, some dangerous and some not so dangerous. He should be evaluated.
Yes. High fevers are not uncommon in young children, and are not always serious. You should try to bring the fever down asap with Acetaminophen and/or ibuprofen. The child should be seen immediately to rule out serious causes of fever.