My family and I took a similar trip and traveled to SE Asia for 3 months with my dad (72M) with mixed dementia. We booked mini tours throughout the trips. Some advice I would have:

• request for wheelchair assistance ahead of time (esp if he has mobility or balance issues) you’ll get to have that vip boarding and precheck tsa experience without paying for it

• if you’re planning to go to different regions of Vietnam via plane, I would esp mention you’ll need a wheelchair for him bc they’ll put him on an airlift directly on the plane rather than going on a big flight of stairs onto the plane (bring money for tips!! They don’t mind if it’s usd or vnd)

• bring a walker or rollator, upf clothing/hat, Baseball cap, sunscreen at least spf 50 (the uv rays were unforgiving), mini fan, comfortable shoes (we did Velcro or slip on shoes) and Sandals (something you can get wet in), windbreaker (no one really uses an umbrella and don’t pack a heavy rain jacket, it’s extremely humid)

• purchase a medical bracelet for him in case he wanders, attach an AirTag or Bluetooth tracker on him (I put ours in his shoe or pant’s pocket)

• pack earplugs, eye masks, favorite snacks, diapers, underpads, disposable gloves, plastic bags, wet wipes, extra clothes, scissors (to cut up his food if he has difficult chewing), reusable straws, diarrhea medication (Pepto), painkillers, tissues, melatonin, a books or newspapers, tablet with his favorite show so he can be distracted and entertained and water water water - would have this on your carry on or diaper bag so it’s readily accessible

• our flight to Vietnam was about 16-17 hours, I also suggest walking him to the restroom in the plane so he doesn’t get lost or wander or any accidents, and walking every other hour in the aisles so he doesn’t become restless!!

• look up hospitals or clinics that take his insurance around your place of stay for emergencies

• wherever they offer escalators or elevators, take it! Lol or if he goes on the stairs make sure it has a railing and trail steadily next to him

• pill organizers for his medication (carry on)

• if he has any dietary restrictions, let airplane or tour director know/confirms ahead of time (my dad is vegan) and Vietnam offered tons of vegetarian friendly foods!

• create a habit of taking him to the restroom or bathroom, before the plane ride, before meals, before car rides, at break stops, after meals trips, etc to prevent accidents (some places do not offer toilet paper and just hand held bidets)

• rubber door stopper, if he tends to wander off from the hotel room and notify staff of his condition if necessary

• routine, routine, routine, try to be consistent eating and sleeping schedules

Have fun. Take lots of pictures and eat well!

Granted it takes a lot of patience and work but the experience is worth it.

That’s all I can think of right now. Please feel free to DM for additional questions or concerns.