3 years ago my wife and I took my parents, in laws and uncle with his partner on a 44' cat for a week. Dad was severely overweight with a fused ankle and limited mobility. MIL had been hospitalized earlier in the year for 8 weeks leaving her very weak and uncle's partner has Parkinsons. Four of the 6 had bareboat experience so at least we started with some experience.

First advice is have patience. Lots of it. Nothing happens fast on a sailboat and with elderly it's even slower.

Took two days of my uncle seemingly attempting to ram the bow of the dinghy up the stern steps so people could climb over the bow of the dinghy onto the steps before I convinced him that the parallel to the hull thing was better. With help at the dinghy bow and stern to hold it steady to the yacht, all the folks were able to easily sidestep onto the stern steps.

Someone mentioned docks. Cooper was tough for them to climb up but they made it. Slowly. Very slowly and with help from those more mobile. Dropping on shore then moving the dinghy is also an option but sometimes water movement isn't good for the already unsteady.

Baths only from a cab or car. We didn't know of the change. Got everyone in pretty easy but there was no way in h*** my 350lb father or the parkinson patient was pulling himself back up into a dinghy. Seeing the situation, one officer told us it was ok to pull the dinghy in to get them while the other one screamed at us over and over not to bring the dinghy in.

Bring games(at least cards) for the boat. When it's raining, regular crew will throw on a garbage bag and head to a bar to get off the boat. Putting elderly in an overly slippery dinghy wasn't an option so we had a couple days of staring at each other in the galley.

This one is odd but ... make sure the heads have a plunger or something to break up stool. Many elderly are on prescriptions that cause constipation. Boat heads can't always handle it.

Plan a day or two or three in a slip. The extra cost is offset by their peace of mind and ease of getting around.

One more time, patience. They move slowly so as you're scrambling to moor the boat or hang a fender or tighten a jib sheet, they're likely to be in the way and not moving quickly enough for you. Just accept it. The pace on the boat is generally just slower than normal vacation mode and that's ok.

There are never enough experiences with out folks so just relax and experience it at their pace.

Sadly it took my about 3 days on the boat to get there but at least I did.