He has to join the school domain to use the softwares provided
by the school, otherwise, he will be deemed as someone trying to
gain access to SP.
All softwares used in polys here are licensed, so you need to
verify yourself to be part of the school. One way is to join
domain. Then you will be able to download and install the softwares
(maybe no installation, he has no administrative rights).
Whether or not he gets the laptop from school or outside, he still
has to join domain because of this reason.
Another reason for using a domain is because of security reasons.
Most people, no matter how tech-savvy they are, will always do
something that will compromise a company or school's network. By
being in a domain, the administrator will know what is going on
throughout the whole network and quickly fix them if something
happens.
