I am guessing that your computer does not have the music library your #1 son has right? If your music library simply had the music #1 son has then simply sync the same songs to #2 son's ipod.
If this is not the case then there is NO way of getting music from #1 son ipod to #2 son ipod directly without going thru the computer. Hence it is vital to have the songs from #1 son ipod in your itunes music library for #2 son ipod to have the same music as #1 son has.
(confused yet???) 😟
So you either need to get the music from the #1 son ipod to your computer itunes library or say that #2 son is out of luck. which is not good 😟
So look at this link of a previous discussion for software that will get the music from the ipod to the computer.
How to get music from ipod to computer
THen it may be good to read this article on how to manage multiple ipods with one computer.
Multiple Ipods with one computer
(And i did not mean to categorize one kid as better as the other by the usage of numbers 😟 ...... they are all special!)
Hope this helps
GFF 🙂