Q. Father was hospitalized and went into intensive care the day before Erev Pesach. Before he was given sedatives I reminded him to do bitul chometz which he did. I’m taking care of business for him and I sold early next day his chometz via a message on the phone of his rabbi, since I couldn’t leave the hospital. But the Rabbi claims he didn’t get the message on time. Can we still use the extensive spirits collection he owns after Pesach? It is a hefsed meruve and an added source of stress and  unhappiness?

A. Shulchan Aruch (O.H. 448: 3) rules that even when one was accidentally unable to sell his chometz before Pesach, it remains prohibited after. However, Biur Halocho (ibid.) quotes Poskim that are lenient when one annulled the chometz before Pesach. Especially when it was an obvious mishap and force majeure, not given to be used deceivingly. (See Sidur Pesach Kehilchoso 11: 20).
Although Mishna Berura (442: 4) and many Poskim rule that “yain sorof” or alcoholic distillates made from grain (such as whiskey or vodka) are considered Biblical chometz, some are lenient and view them as only ziah or “sweat” and not proper chometz and therefore only Rabbinicaly prohibited. (Pnei Yehoshua O.H. 13. See Shaarei Teshuva 442: 3). That being the reason that many who are stringent in selling proper chometz are lenient on selling liquors and spirits.
Horav Shlomo Miller Shlit’a added another possible leniency that should be checked, namely that many chometz sale-documents contain a clause that incorporates all those individuals who attempted and wanted to be included in the selling, but were unable or forgot to do so.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit”a