Dad's declining physical abilities... how to help him acknowledge it.

You might offer to video the graduation and send your parents a copy so they can watch the graduation at home. By any chance will the graduation be on a podcast, or something live that could be watched at their home if the local relatives set it up on a computer?

I'm not really sure how you could convince your parents that this is a better alternative though, other than convenience, safety, cost and similar factors. It is hard to convince some older men that they're losing their skills and long distance travel isn't safe.

Lots can happen in the next 10 months. I think it is too early to start stressing about this.

It what way is it "too risky" for Dad to travel? What might happen? Things might stay as they are now, or they might get a lot worse. Or Mom may have trouble traveling next year. Play it by ear for now, and do the real planning in six months or so.

I'm also wondering what the risks are for dad to travel, airports have lots of services for people with disabilities, and if your home isn't suitable for him to visit there are hotels with accessible suites. Perhaps if you are more specific about the barriers you foresee we can offer solutions.

As time comes closer to graduation, feel free to use what are called "therapeutic fibs" that one uses to help an elder with decisions.

Example, "Suzy" is going to be away with friends for the weekend right after graduation. You know how independent kids are today.

Could your daughter visit them after graduation? I know it would not at all be the graduation gift of her dreams, but she could just fly out for the weekend and visit relatives and grandparents.

Or would your folks go for the idea that instead of paying for travel they could give your daughter the money for a computer for college or new clothes for job interviews? That way they'd still feel like they are being involved and supportive grandparents.

My mom has pretty bad mobility,, but she and my 83 year old aunt just went to Vegas for 3 days! family met them on the other end at the airport.. we got them on here. They had lots of help on both ends, and had a great trip. I get the idea you sort of really don't want dad there...you are not horrible,, we all have family like this! I'd love to go on a local vacay without FIL wanting to come and run the show! I agree with waiting until closer.. so many things could change!

Thanks everyone for your thoughtful responses. True, graduation is many months away. However, having them comment on buying airplane tickets, reserving a hotel, etc. makes it difficult to put things off until the time gets closer. I tried to convince them to wait until it gets closer to plan anything because a lot can happen between now and then but...they don't see it the same way. The risks with his travel involve my home - stairs everywhere! I was so nervous the last time they were here (2 years ago). Since my original post, my brother has offered to be a travel companion to help out (if we can't convince my parents not to come out) which would be a huge help! Again, thank you all for the thoughtful and excellent suggestions! I'm going to take some deep breaths, lean on my siblings for support and hope for the best :)
With any luck, I'll be able to talk with my mom about some alternate plans (live streaming, etc) and see if she has a change of heart.

Anything can happen in 10 months!! I'd try to not even engage in conversation about this with them. As sweet as it is to want to be there for your daughter's day---reality is that it's just HS graduation, not college or a wedding....I guess I look at HS graduation as a "must do" thing---my kids had no options, and I told them we'd save the parties for college degrees :)
One thing that can be a saving grace for you--as it was for me. Our HS allowed each graduate 2 tickets. Period. So only parents could go. It was simple to keep my feuding FIL & MIL away from each other at my son's graduation which coincided with their divorce....I just said "Oh darn, we absolutely cannot get more tickets" (and my son was Sr. Class President!! Still got 2 tickets.) A little white lie may solve the problem.

And if your dad is a pain to have around, how not-so-joyful would that be for your daughter. It's about HER, not pleasing him.

We videotaped the whole ceremony, with my son directing, and speaking as class valedictorian. NEITHER OF THEM EVER WATCHED THE VIDEO!!! So--I'm sure the proceedings will be taped and made into copies. It's not the same as being there, no, but again, sounds like you REALLY don't want this hassle.
(FWIW, I find any kind of graduation ceremony mind numbingly boring and my kids have collectively 2 MDs, 2 PhD's and 1 JD. ) Plus all the BA's and BS's. I'm super proud of them, but could have happily skipped all the extra speeches. (I have a lot of kids who are over achievers, for sure)

Good Luck.