No you can not remotely download to his. If your Verizon though, you can look at his texts through your online account. Not sure if other's have that option or not. Download the messenger from the site and use his phone number and you should see all his texts. Good luck'
Best spyware and free is in google play apps. Has a bird on it. You will need the target phone on any application out there so just go for the free one. It forwards all messages to your email.