As a father of two, I would also highly recommend downloading the Technic Launcher as it has the lowest learning curve. Neither you or your son needs to learn how to install mods directly... just install the Technic Launcher, search for a modpack that has JurassicCraft in it, click Install, and then click Play after the pack has been installed. You don't need to worry about installing Minecraft or Forge or specific mods because Technic handles all of that stuff.
There might be some trial & error in terms of which modpacks your son likes best, but... if he's anything like my kids, once he sees what's available, he'll quickly get the hang of it and find one that he likes (and probably a lot of others as well).
The only thing to bear in mind is... some modpacks contain a LOT of mods, and your son's laptop might not be capable of running some of them, so... again, there might be some trial & error finding a 'light' modpack that only has JurassicCraft and a few other mods, which will run much better on a lower-spec laptop.
You could maybe try this pack first, which has 79 mods and is pretty popular:
http://www.technicpack.net/modpack/rexx ... ack.662762If that doesn't work, this one has half as many mods and has just been recently updated:
http://www.technicpack.net/modpack/real ... ark.784002Hope that helps.
Good luck!
