Reddit reviews GamerGrip Total Grip Solution Stops Sweat On Hands for up To 4 Hours for all Sporting and Gaming Activities

You could always try Gamer Grip. It's a tad on the expensive side but you can make it last, and it DOES actually work, from personal experience.

Otherwise yeah, maybe a new shell or grip attachment could help, but I have no experience with those things.

I've heard several people mention GamerGrip. I can't vouch for it myself but it suppose to work well. https://www.amazon.com/gp/aw/d/B00W1T7B1O/ref=mp_s_a_1_1?qid=1452002723&sr=8-1&pi=SY200_QL40&keywords=gamer+grip&dpPl=1&dpID=41bXMC7qyAL&ref=plSrch

Get him some Gamer Grip, that stuff is great and under $15! https://www.amazon.com/GamerGrip-Total-Solution-Stops-Sweat-Hands/dp/B00W1T7B1O/ref=sr_1_1?ie=UTF8&qid=1480978490&sr=8-1&keywords=gamer+grip. Under $10 on the scufgaming.com site, but maybe end up more than Amazon after shipping. BTW-If you ever do look into buying him a Scuf, I would lookup Cinch instead. I have both and Cinch was cheaper and they are arguably equal in which one is better. Spending that kind of cash though, either way, it would be better to let the cat out of the bag and let him choose the build customization, unless you know exactly how he likes to play.

Gamer Grip is great, and sold by Scuf:

GamerGrip Total Grip Solution Stops Sweat On Hands for up To 4 Hours for all Sporting and Gaming Activities

https://www.amazon.com/dp/B00W1T7B1O/ref=cm_sw_r_cp_api_i_T.nKDb8252PHJ

Here's my recommendation
GamerGrip - Total Grip Solution - Stops Sweat on Hands for up to 4 Hours https://www.amazon.com/dp/B00W1T7B1O/ref=cm_sw_r_cp_api_FI7nxbBA1H247
I use this for playing call of duty. It keeps your hands dry. I was having the same problem with the pencil and I have this a try. It works great.