My husband (85) is still able to get around pretty good. He suffers with depression and mild cognitive impairment. Why doesn't he complete anything?

This last couple of years he has developed a strange habit. He doesn't complete anything! He sweeps the floor in the barn - leaves the pile. Mows the yard - leaves the mower out. Cleans the gutters (yikes!) - leaves the ladder up. He empties packages in the refrigerator and leaves the empty bag. Gets chips - doesn't close the bag. Does some dishes - leaves some, never finishes, leaves the dishwater. Runs the vacumm - leaves it out. Takes off his shoes - leaves them in the doorway. Washes/dries a load of laundry - folds and leaves it in the basket all week. I could go on and on...... Please don't get after me saying I should be glad he is able to do all these things. I am. I am wondering if this behavior is an indication of something, mental, social, or maybe even physical????