All the above is good advice... first thing to remember is that your sister and you are in shock and will be for a while. Rely on trusted friends to look over your shoulder. When my father died, my wife, and I, who both graduated law school, my brother who has a phD. in theortical math, me mum, who had been an executive, made some of the most silly oversites in managing my dad's estate, as we were in shock.
I agree, that it is likely not a good idea to dispose of his clothes right away. Making gifts of them to friends is often a good way of keeping a wee bit of him about for a while, to sort of ease him on.
Holding you and your sister in the light,
Larry