How do you tell someone their child might be autistic?

Today I was asked for some advice.

"My brother's little boy seems to behave quite oddly sometimes," my friend said. "We're a bit concerned that everything's not really ok. But how am I going to tell him that?"

This is a tricky issue. It's not your child, and yet you can see that something might be going on, and you want to help the child, but maybe the parents are unaware or possibly trying to ignore it, and is it really your business anyway?

When I asked my friend what he'd noticed about his two year old nephew, he described behaviour like crying in big groups, putting his hands over his ears and screaming at noises like running a bath, and going limp and floppy in the swimming pool. There was also the possibility of a language delay, although it can be hard to tell at two.

My advice was to avoid the 'A' word, and instead focus on the behaviours. If it was my child, I'd immediately be looking into sensory processing disorder or auditory processing disorder, so I suggested that they say something along the lines of: "I was talking to a friend who has a child who does something similar to little Bobby. Her child ended up having auditory processing disorder - it's where the brain isn't processing the sounds the child is hearing properly."

Then I suggested that they focus on the thing a lot of parents in that socio-economic bracket care about - the potential academic ramifications - and add something like, "Apparently it's good to try and get it sorted out before they go to school because it can hinder their progress."

Personally, I think it is good for friends and family to help parents to pick up things they may need to sort out for their child. Obviously, great care and tact is needed, and things like this should only be done if they think they see a serious problem. The other thing to say is that you probably only get one shot at it. If you tell them once and nothing is done, I don't think you can go back again for a second attempt. They will have heard you, no question. The ball is in their court, and you aren't responsible.

What do you think? Would you tell a close friend or family member if you thought their child had a serious learning issue or disability that no-one seemed to be talking about?