Not available for arm, cannot be installed on Raspberry.
If he really wants to use it on a Pi and is already using docker (I personally love wetty)
Code
docker run --restart=always --name=wetty -p 2222:3000 wettyoss/wetty --ssh-host=your-server-ip -b
All you need to do is adjust "your-server-ip" to your server IP and deploy. Wetty will then be reachable at ip:2222