You may have books in your local library on table top gardening, and also on terrariums.

Personally, I'd rather have a table-like garden than a raised bed because gardening 'sidesaddle' is something I find uncomfortable.

You might also want to check out books on gardens for people with allergies, scented gardens for people with poor sight, and gardening for kids as some seniors aren't used to slow-paced gardening.

Be careful with prickly things - wounds can be slow to heal - and bruises from accidental bumps.

Lightweight garden tools but of good quality are important. Please remember that tall tools for short people is a recipe for misery. Double action secateurs can be a blessing for people with small hands or low in hand strength.

Remember lots of warm, sheltered sitting spots with pleasant views or garden treats. And handrails in awkward places. Downhills are just as tough as uphills, unfortunately. All steps broad, wide and shallow. Excellent lighting in sheds. BIG print on any chemicals. Reading cn be tough with cataracts.