Is im echolalia a typical [i.e. normal] part of autism?

My brother has classical autism and this is part of a Facebook conversation we had a couple of nights ago.

He does this with everyone he talks to on IM/Facebook chat/whatever and it really pisses me off [I'm also on the spectrum, but that doesn't stop me].

However, is it typical of people on the autistic spectrum or just him? Whatever the answer is, why would somebody on the spectrum do that other than maybe understand what is being said to them or retain the information as best as they can...?

The text has been unedited.

* * * * *

He was telling me about how his throat infection was on the mend and I told him I was ill too.

M=me, B=brother.

M: that's good... guess who's also ill?
B: Who is ill then?
M: me...
B: I am guessing you had a throat infection aswell...
M: Ummm - not far off.

Sinus infection and upset stomach. GUGH

k6
That k6 is meant to be a sick smily

B:I know who is ill and it's you...
You're illl with a Sinus infection and upset stomach. tell me about it and the k6 is meant to be a sick smiley.
k6.