Sorry for the loss.
Did he have any family that might want them ?
I know that & I hope this is a long ways out yet...But when it dose happen I know my dads collection all goes to me & my 2 boy's.
Just remember that the brass items are going to be you high end items so don't just give them away to strangers.
I know that when we sell HO my dad marks all cars around $5.00 for standard couplers & $7.00 for kay-dee couplers. Then add $1.50 for metal trucks & another $1.00 if it has a box.
Engines are a whole other story. My dad has a bigger list on them as far as what he sells them for. You might want to consider going to a train show & just shop & get a feel for what things are going for.
Just remember what one person charges for his or her items might not be the same for others. Like my dad & some of the HO he was selling at a show. Our prices where lower than most but we where higher than some others.
I hope this helps you out.
Take care.