My deepest sympathy for your loss also, I can't imagine dealing with the loss of a child.
You have come to the right places, there are many long time trustworthy collectors on this forum & you are much less likely to be taken advantage of here, compared to many other platforms, I'm sure there are collector for most aspect of star wars collectables on here, be in vintage or modern, as has been said above, best thing is just take your time, take some good clear pictures & post them here to gauge your sons items values & then you will have a good idea of what you have & what it's value is, then you can decide where is most suitable to sell, here is a good starting point though as you know your sons cherished items would be going to a place the items will be appreciated.