I don't know if your Dad has passed or not. Mine has. That colors my viewpoints on this collection.
Those models are a connection to your father and a hobby you both shared. When you look at them sometimes you'll only see plastic kits from fifty or sixty years ago. At other times you'll see your Dad, his joy and the love you shared.
I inherited a large model train collection. Most of it is insignificant to me. There's an unfinished garden railway that I'll have to remove prior to selling my parent's house when that responsibility falls to me. That will be a hard project. I also received an old Tyco General Engine that may not run. Its where Dad left it. Every time I go into his train room and see it, I remember him. Most of the trains will be sold on eBay or at train shows. The General will eventually find its way to my office or a special shelf at home.
Keep those kits.....I can identify most of them for you....most have been reissued. Their value is minor compared to what that connection with your Dad means to you.