It's always hard going through someone elses stuff, I'm sorry you find yourself doing this.
I would definitely suggest a 3 pile system. I Will keep, I might keep (then be ruthless with a 2nd look) and I'm not keeping.
Have you spoken with your family, see if anyone wants any of it?
Perhaps list them here and have a PM auction to raise some money for the CA charities?
My mum put it in a pile to see if I want it & my brother doesnt (he lives in Oz but I still ask) I generally keep what I want but the rest I put in a pile to sell / give away. I have sold somethings and put the money into a account till we decide as a family what we are doing with the funds as in to take a trip to scatter his ashes and some to charity etc.
I will have a look to see what can go into the CA Raffle as some isnt worth it IMO