Whole collection of vintage rare baseball, football, and basketball cards

I got these from my dad and he said there are lots of rare and vintage cards in the collection the box has thousands of baseball, basketball, and football cards and this is my dad’s whole collection. He said I can easily get thousands of dollars for the cards that are in the collection but I don’t feel like going through the whole thing and risk damaging the cards knowing that they are in really good shape after decades so I’m just going to sell them for a reasonable price even though he said I’m going to regret it because how many expensive cards are in there. They are ready to ship to!!!