That's quite a haul, have fun.
I'm almost the same age as your "friend" and I remember when if you wanted extra detail you had to make it yourself out of whatever was at hand. In my current projet I'm still mostly doing it this way with some use of left over parts from kits and P.E.
With the advent of printed parts, this will continue to grow and those people will have an advantage over the previous forms of parts. It happened before when resin started and then again with P.E. You'll just have to live with and adjust to it. As long as the builder lets it be known during a contest that detail parts are included from other sources, it will eventually come down to the builder's skill and the look of the finished project.