I'm thinking about charity gifts, such as adopting a tiger in Laos, a vegetable plot for a family in Bangladesh, or training a teacher in the Philippines.
Or alternatively home-made gift tokens, such as "I promise to send you a hand-written letter once a month", or "I promise to telephone you once a week" or "I promise to make you a quilt by this time next year".
One of those would be good for my dad. For Ed the gift token would probably say "I promise to cook your favourite meal once a week and not even serve salad with it", or "I promise to blow off choir practice, committee meetings, marking etc. once in a while and spend the evening with you", or "I promise that for one whole weekend I will let you choose all our activities and not demand that you do any gardening, DIY, shopping or drag you to a craft fair or farmer's market against your will".
So go on, dad, Ed - take your pick (you only get to pick one, though!)