I guess he's right, many research has created different outcomes. But they all conclude the same message. Oral sex is not a sexual encounter to be worried about too much. You can calculate your hiv transmission odds online at a non-profit organisation website (www.hiv-testing.com). It could be of help.
That,s just his opinion i guess but the majority say zero risk.I would stick with the majority.The exact same thing can be said about the window period.Some say 4 weeks,others 6 to 8 weeks and then of course the official window period which is 3 months.Don,t let it confuse you,there is plenty of data out there to support the zero risk fact and a 3 month window period for a conclusive result.