have you tried melatonin for the sleep issues?
does your ds2 have a paed? I think you need it prescribed by a paed, but haven't used it myself, so not entirely sure.
but otherwise, yes - in bed, and calm is better than not (we went through this with dd1, who did not sleep until about 10.30 or so some nights (she wa sonly about 4!) but she used to be ok by herself, with a few books to leaf through.
it is easy to fall into the cycle of shouting - most of us here ahve done it. I know I have - and it does just escalate. knowing you are getting into this is the first part, and well done for trying ot address it. identify your trggers too - it may be your ds with the ASD< but you will have triggers which set you off onto the cycle of shouting. trying to work out in advance what they are, and how to deal with them might help.
it sounds a bit silly, but one thing we have done with dd2 (NT, but hovers around the edge of the spectrum) is role play through some situations which were previously getting us all snarlign at each other. pick a calm time, and try to work through a situation which would (if it arose in normal daily life) usually spark off a row/upset/whatever. giving your ds (and ds1, and dd as well) the right phrases to use, in a non-stressful situation might help avoid the inflamation. maybe something like a 'time out' phrase they can all use when they feel they are getting stressed? the other children have to always take heed and back off (appropriate rewards for doing so).
some posters have had success with an 'emotional volcano' - a scale of 1-10, with appropriate colouring, as a visible reminder of how the person is feeling - stick it on the fridge, and getting people to recognise (and I mean everyone, not just ds2 - part of the identifying triggers bit) exactly how they are feeling, and be able to tell the others is very important.
well done for trying to turn this around. it can be done, but it can be tricky feeling your way through.