The exploit itself is a bug in the Linux kernel so it will most likely work on the device, however the problem is getting it to execute. Thus far the towelroot exploit is an application you run, so you'll need to install the apk first. Since this isn't possible on the Sony readers the exploit itself needs to be ran in some other way.
So first off the source code for the exploit needs to be released. All we know is that it is using the
CVE-2014-3153 bug in the Linux kernel. If he doesn't release the source, someone needs to make the exploit all over again so that it can be modified to be executed in some other matter as an apk certainly isn't going to do it. Then all we need is some way to execute it on the device, which isn't easy considering USB debugging is turned off, adb is turned off, recovery and all other types of communication with the shell is turned off requiring some way for the reader to execute the script with the exploit in some way.
So will the exploit work? Yes. Will it be easy to implement on the PRS-T1, T2 or T3? No.