Outlook - Suggestions to resolve emails being converted to plain text

Hello
Just wondering if any one has any suggestions to try to resolve this problem.  I always receive emails from a certain person within our company in plain text - I don't think this is necessarily to do with Outlook as I have my work e-mails set up on two different PCs and it happens on both.  Both email addresses have the same domain name and it only happens with his email address.  And it happens to every single email.
Does anyone have any suggestions of things to try?  Maybe something needs adjusting on the server?...
Regard
Peter

The person has their email client set to send you emails in plain text.

ok - hadn't thought of that, I didn't realise it could be done - do you know how to fix this?  he uses outlook 2010.

It is in the "Options" section for Outlook.  Look for something about Composing Messages.  It is RichText or Html by default but can be adjusted to Plain Text.