How can I set up and email address for my grandson without giving him general access to the internet? email only

My grandson's school needs him to have his own email address. For some reason, his is not able to use my address. I do not want him to have general access to the internet. His older brother caused my computer to be infected with a virus in a very short time. It took three weeks and one hundred dollars to get the use of my computer back.

I do not want him to have access to the internet, but his school wants him to have an email address to communicate with him about school work. I am concerned that once he has an email address, someone (not the school) will send him a web site address in a message and he will be able to just click on it to get into the internet.