The more full time you are on the boat, the more work there is to do. The more you loosen the boundaries of your sailing and head
out into the deep blue, the more work there is. There are always chores that have to be done on a boat, projects to undertake and complete. Often what is easy for us here in North America, isn't so easy off shore. For example, read Lin Pardey's article in this issue of Cruising about food shopping
in foreign countries; and how long it takes her.
However there is much down time in sailing and that is the attraction of the "Zen" of it. Sailing forces you into the moment and this is one of its chief attractions. To use some old Christian language, your father is caught up in "salvation by works." In other words, his worth is found in his works. By letting go of the cultural values that suggest our worth to ourselves and others, by the "works" we have provided, we discover other reasons for self worth; this is something that meditative monks learn after they have "settled" from their previous secular life.
If you your dad reads this past paragraph now, he'll probably say "What to he.. is he talking about?" If instead you taking him sailing for a month, then let him read it, it'll make more sense.