You take the fabric seat off your doll's buggy and use it as a play hoist-sling.
You change your doll's nappy and give it a bottle and then give it suction too.
Your doll gets to play a bit and then do physio "big stretches".
You know the format for a proper medical handover and tell the doctors what is wrong before your parent gets a look-in.
You can count the different medicines and turn the feed pump on and off more easily than the babysitters.
You know when your sister needs help and when she's just teasing you.
You understand your sister can't move towards you and so you deliberately position yourself within reach so she can kick you - and then you come to Mumma telling tales!
You accept the fact that your sister needs a lot of help, and in fact you see your sister needing so much extra help that you refuse to accept that you might also have disabilities of your own which might limit you somewhat.