I Have My 21 Month Old Grandson Here And He

I have my 21 month old grandson here and he woke up early this morning with a temperature of 101.3. We gave him motrin he went back to sleep. When he woke up again his temperature was 99.8 and started to climb. We gave him motrin again but his temp peaked at 103.7. It's been up and down but not below 101 all afternoon. He will not eat and will only drink a little every once in a while. What should we do, please