transfer of device

Short answer: Yes, a gateway from one account can be used on another account. 

A couple things to consider, though. If the gateway was on your friends account when it was cancelled, the system automatically tagged it for return. Since it was not returned, there may be a non-return fee on that old account. If that is not paid, then the device would be blocked and unusable. If that was paid, then you should be able to use it as long as the address that you want to use it at is eligible for Home Internet service. 

Most of the time we suggest that you get a new gateway directly from T-Mobile when you start a new Internet line to prevent some of those weird situations that can cause you more headache. The gateways are free to use with the service, so you don't have to worry about any upfront cost or any kind of rental fee over time. 

Hope this helps!