Yes. I have to. He is 14 and usually helps out half-willingly although teenage hormones are giving him a bit of an attitude at the moment unfortunately. DS2 is 6, quite severely disabled and extremely high maintenance. I need and expect DS1 and DD (7) to help me (or DH) out quite a lot when either of us are not both present to deal with DS2 needs.
DS1 is compentent at bathing/dressing/lifting/carrying/feeding DS2 although he doesn't change nappies and I don't expect him to. Both he and DD help out frequently with changing dirty nappies though as this is a two person job. They both also have to help with a lot of tidying up of the house (although not actual cleaning/housework) as DS2 tears through the house like a whirhwind leaving chaos and destruction in his wake!
DS1 does quite often clean up the kitchen after meals though.. load dishwasher/sweep floor (near where DS2 sits!!) and wipe over surfaces.
DD supports DS2 in the bath and while I wash him. DS1 is often left to 'babysit' DS2 for short periods although with DH and/or I in the house attending to other things (quick bits of housework usually often when the other one is out.)
DS2 needs constant attention and the only relief from that is plonking him in front of Nick Junior for half hour or so at a time (will lose interest after that and become high maintenace again.)
It's not what I would have chosen for my other two in a million years.. but as I am aways explaining to them, we are a family and DS2 is their brother and helping each other with him helps us to cope as best we can as a family and be happier. They do love him and we all get a lot of pleasure from him it has to be said. He has such character and sense of humour and they both love teaching him 'bad things' and rude words!
DD and DS1 belong to Young Carers and get to go to fun groups and out for treats every few weeks.