Value of an autographed baseball cap?

My sister, going through a deceased friend’s possessions found a baseball cap whose bill was autographed Roy Halladay, 13. Normally, I would say that it is not worth much, but:
Roy Halladay died in an airplane crash a week or so ago.
He was a superstar pitcher.
The Phillies (whose cap it was) won the series in 2013.to
As far as I can tell, it is a genuine team cap, not the kind sold in stores. One thing that makes this likely is that the friend did not go to baseball games, but did home repairs and was likely to have done work for Halladay.

And if it does have significant value, what is the best way to realize it.

First thing to do is have the autograph authenticated. The service will cost ~$50, but without a certificate of authenticity all you really have is “It could be Halladay’s autograph”. Once that is done you can have the item appraised by a local memorabilia dealer, preferably one who specializes in sports. I suppose you could reverse the order and get an appraisal based on the assumption the autograph is real, then pursue the COA.

It appears by quick Googling that Halladay’s autograph does have value, but it varies widely based on what was autographed, when and the specifics of what was written. I didn’t see any hats specifically.

I’m not into baseball memorabilia, but this would be a cool thing to have.

*This is a cheapo version.

One just sold on ebay for $200, with authentication. It was a “Buy it Now” offer so no bidding. Jerseys with bidding went for over $200.

The Phillies didn’t win the World Series or much of anything else in 2013 - they came in 4th in the NL East with a 73-89 record. So the “13” isn’t going to do anything.

Nowadays practically nothing, without the hologram of an authenticator to guarantee a purchaser that the article is genuine.