Personally i would recommend getting him sheet music to learn off of instead of tabs, he will learn a lot quicker and will learn several things at once from it (learning to read, learning note names, learning where the notes are on the bass, timing, keys, etc).
Dont get me wrong, I went for years without learning to read music at all, quite a few years actually. I have nothing against tabs but now that I took some time to learn to read music I have no idea why I was so against it all those years. I have learnt so much in a short time because of it.
Either way its yours or his choice, back to the question.
Easy songs to start....
Knowing what kind of music he likes would help pick better ones but quite a few nirvana songs are pretty easy, kiss, green day, offspring, etc.
One thing you may want to look into is getting the Hal leonard bass method book 1 and the accompanying Easy pop bass lines book. They are under 10 bucks each I believe and will teach you right from the beginning.
The method book will teach hand position, how to read the notes, timing, etc, with backing tracks on a cd to play along to and the easy pop lines book has full songs to learn (some of them are a bit simplified for starting) like john lennon, beatles, nirvana, deep purple, beach boys, blink 182, dire straits, think there is something like 20 songs in it to learn with a cd as well.
Anyways just my 2 cents, if you want to go straight tab 911tabs.com is a great place for finding free tabs.
