Computer security for senior

Looking for ideas for security for an 86 year old.

His eyesight is bad, really bad, he zooms so words are 100pt font to read anything.
He reads emails and checks investments online. Concern is he is highly likely to fall for a phishing scam. Mainly due to his poor eyesight.

Locking him out completely is not an option. So trying to figure out what would be best.

Can go two step authentication on some accounts, looking for additional advice.

Thanks.