Yes. It's stated in the scene that silver is Barnabas' vulnerability. Quentin was about to stick a pin in the doll's heart, but he's told, "It must be silver." When he starts pressing the head of the cane onto the doll's chest, Barnabas is instantly incapacitated by excruciating pain. But Jamison faints and while Quentin tends to him, Magda rushes in, so the ritual is ended.
I must point out (1) Barnabas handles that cane all the time, to no ill effect, and (2) Likewise, he handles wood--which we know to be fatal to vampires if piercing the heart--with a similar lack of concern.
Exactly. He can come in contact with either unless they pierce his heart.
Though early in the show, Barnabas tells Maggie that the wolf's head is an alloy of gold and silver, presumably as a way of explaining how he's able to carry it, but once the cane becomes synonymous with the character, this is never mentioned again.
You don't interpret the evidence provided on the show to mean that silver is detrimental to a DS vampire, and I do. Agreeing to disagree is cool with me, Zahir.