Is the issue only with IE8? Since he's getting boxes, and if the problem is with all browsers, it is likely he does not have Arabic fonts on his machine. If it IE only, and if the browser is configured to something other than utf-8, he should still be getting printable characters; just not the right characters. Without more trouble shooting on his machine it's all guesswork.
On a side note, the Arabic font has such a low aspect ration (en height ÷ em height), it is very hard on the eyes. I'd suggest going at least 50% larger.