I decided at least ten times today not to respond, but being me, I can't ignore this one any longer. After only four words into your post the problem became readily apparent------he's your "BIL" !!! That's the problem straightaway. WHY? Because more frequently than not, in-laws seem to be able to say the dumbest, meanest things, yet they always remain "safe", by marriage. Or at least they feel they can.
I think everyone here is being far too kind.
Imagine....he's in Orlando, land of the outrageous theme parks and mega-resorts, and he's complaining about an "excess" of $11 for a greens fee?? Wow. He has no clue.
At Hilton Head there's a great golf course that guys die to play.....Harbour Town Golf Links....and the fee is $250, and most are ecstatic to pay it. They even go home and brag about it. Strange, but it's their little "red badge of courage". An article googled says most HH course average around $100. So your $61 fee is WAY below average for a resort area course, and GV's course is nice, as you point out! He should count his blessings. He's there because of your generosity, probably to your sister and not to him, but that's irrelevant. He's along for the free ride, I presume. Sure sounds like it. He's got some gall to say a word.
Face it, he's a jack-leg. Say you guys play three rounds---that's only a $33 "surcharge" in his eyes. For Orlando, on a FREE VACATION staying with you, he should be something other than the "North end of a South-bound mule". (Being from Montana, maybe he would understand that metaphor.) Frankly, he should be paying YOUR greens fee! Can't believe he's complaining about possible forking over an extra $11 per round..... in Orlando....on vacation.....when the accommodations are free.
Personally I wouldn't give him any "difference money"......not one dime. That's a joke, and only makes you an enabler. Are you going to "pay the difference" if he orders a steak when out to dinner? It'll never end.
So I strongly disagree with others here. He's a cheapskate. So, the fact that YOU'RE also HIS BIL, you now have the right (LOL) to say anything also, and remain safe. I know, you don't wish to create waves, and that's commendable, but you should at least print out a few of these posts and put them in his suitcase for some pleasurable reading. Sadly, I know his type. And I truly despise ungrateful mooches.
I'd most likely get up the first morning and head to the golf course without him, and remind him later that he "didn't wish to play there". End of story. Maybe he'll cry. Let him find and pay for his own activities. MAYBE it will change your FUTURE if he understands your stance. You are not wrong for your concern, and this is really not an earth-shattering dilemma, but it's something that will no doubt continue to nag you, until you make your feelings known.
Good luck. I also have one of these....a cheapskate BIL, and yes, he knows my feelings, and he doesn't get anything from me. But a grateful person gets anything and everything from me----it just works that way in this life. I'm a giver, not taker, but sometimes you just can't stoop. I don't feel better yet having posted this, but maybe in a while.....forgive me if I sound a bit over-worked. I just know how one little comment can ruin a good thing sometimes. Keep us informed please.....and have a wonderful week if you can...ha ha. If you bite your lip too severely, I'll sew it back for you.....