It was probably his own smartphone which was already equipped with all the tools he needs and a server running somewhere. If it's a new smartphone and you haven

It was probably his own smartphone which was already equipped with all the tools he needs and a server running somewhere. If it's a new smartphone and you haven't done any preparation at all, then simply installing an SSH/RDP app and renting a VPS somewhere is done in like 10 minutes. I don't see any reason why you would actually need to root the android device and do everything locally. That may be a fun thought experiment, but it's completely unnecessary in practice.