When the twins turned one an artist-friend painted them a little duck each and framed them. The pictures hang over their beds. Except that yet again Ino's picture is with the framers because yet again his brother Tom has smashed it.

Now the twins are 12, I thought we'd got over all that. Seems we haven't. Ino was singing in the morning and Tom just couldn't take any more.

Ino is getting increasingly frustrated by having to get changed in the dark because the light hurts Tom's eyes and having to stop singing because it hurts Tom's ears. It's good he's expressing that.

It's clear to me now that Tom will have to have his own room. We don't have one. We'll have to convert the garage. Adolescence is on the march. I fear Tom engaging in socially embarrassing sexual behaviour and I need to give him privacy and access to a bathroom.

Ino will need privacy too. He shouldn't have to be a hero. But he is a hero, all the same.

We parents of special needs kids hate the nonsense about disability in the family making us all better people, but Ino is exceptionally kind. I don't know if Tom made him that way or if he was sent specially for Tom.

Tom's autism is pretty mild though he does have a learning disability too. I think being a twin helped him early on. Tom and Ino used to hold hands when they were feeding, two chubby little paws, one snow-white and one dusky. Sometimes they would giggle so hard they couldn't feed at all.

We didn't notice Tom's disability until he was about four. Then he began to "act out" to a shocking degree and our life just about unravelled.

I don't think Tom's sister Roise, who is now 11, has ever forgiven him for taking the spotlight off her. As a girl, she is more aware of Tom's difference as a social embarrassment.

She is getting better about it all but until recently she has been unable to accept the "unfairness" of Tom having different rules. She simply couldn't make allowances because he started out with a handicap. She suspected that if I treated him the same he would stop being "spoilt".

His elder brother Jack (14) went through a phase of trying to discipline Tom. I suppose he was trying to control an uncontrollable situation. That seems to have passed now.

Though Jack winds us up exactly as much as any other teen – and I find it hard to accept that he doesn't cut me any slack given the stress that is already in our home – I think he would do anything for Tom.

When we were discussing Tom's future and the possibility that he might work on a farm in a Camphill community, Jack's only concern was – "Would they exploit him?"

Tom is our pain, our cross, our tragedy. The kids' fondest wish is that Tom's disability would melt away. I think Roise still holds on to the hope that it will.

Tom means we only invite kids home who understand about him and we go through excruciating moments with kids who don't – like the French exchange students who left the trampoline when he got on it. He yelled for them to come back but they wouldn't.

The pain and embarrassment of moments like that will never leave his siblings.

But the Sibshop workshops, created in the US for brothers and sisters of disabled kids and promoted by Autism Ireland, takes as its premise that most siblings of disabled kids are doing fine.

So are mine. They are among the luckiest kids on earth. They pulled one short straw, but they have two parents, health and wealth. They're not the disabled ones.

"Think what Tom is going through", I tell them again and again.

I tell them they won't have to look after Tom and if I thought any of them would end up being his full-time carer I'd be gutted.

I still believe enough in the services in this country and Tom's ability, to think I will be able to find him a home and a community.

I think it's possible they won't resent him. I know they love him. And I hope that when we are gone he will have three strong advocates for the rest of his life.