I’m completely perplexed

What do you think about it? I’m ready for the oil change on 156,BJ 1997,120hp,140TKM. At the moment I have 0W40 in it, the lowest oil consumption (mobile) for a long time, about 2 years ago Castrol 10W60 Just I come from an ALfa/Fiat/Lancia screwdriver (free workshop) and he said I can’t drive the 0W40 at all, the engine couldn’t do that, since I have one of the first (“massive oil consumption”, “everything closes”, “can’t shut down the machine” Those were the sets of him, then he has at the side of the mot or some oil smeared (minimum, the car is already 10 years old) and said that comes from it.I should drive 10w40 under some circumstances 10w60, nothing else.. since I am not the screwdriver among the drivers I don’t know what to do either, he actually has no bad reputation at mor in the area or there are not many alternatives if you drive Alfa here.I know, oil is such a topic, but thought through the countless threads here that I drive 10w60 or 0w40 in peace Maybe someone knows a piece of advice, thank you.