Ten years have passed since Rabbit, Run, and Rabbit drinks more. After work he an his dad usually get drinks. Rabbit always orders a daquiri, then another.
Later in the book, a co-worker he's met at a bar (a "negro" bar, my friends -- this is the end of the '60s) tells him it's a lady drink and has him order a whiskey sour. He is also observed drinking beer as the daquiries seem to taper off.
If a man wants to have a drink with some fruit in it, then a man should have a drink with some fruit in it. But two daquiries a day at the same bar almost every day? This is the kind of man Harry Angstrom is.
At the beginning of Rabbit, Run, he doesn't drink at all. He starts with the daquiries at dinner one night, ordering what the women at the table order. Life happens to him. He moves along till he's jolted out of routine.