I'm sorry for the loss of all the friends that died 'too soon'
I have told my family that there is value in my sewing stuff if they want to deal with the things.
If not, they can give it away to whoever might value it. I would hope that they would give more distant relatives and friends the chance to take what they wanted before they donated it to a charitable organization.
If they burned it - if possible, I would come back to haunt them! (That action I really don't understand - but I have heard of people just dumping trash bags full of fabric because they just didn't want to deal with the stuff - sometimes the effort of disposing/moving on items seems like just too much effort)