Can a spell cast through a familiar be Counterspelled even if the familiar's "owner" is out of range?

Question

The find familiar text states:

Finally, when you cast a spell with a range of touch, your familiar can deliver the spell as if it had cast the spell. Your familiar must be within 100 feet of you, and it must use its reaction to deliver the spell when you cast it. If the spell requires an attack roll, you use your attack modifier for the roll.

The first sentence of counterspell states:

You attempt to interrupt a creature in the process of casting a spell.

Of course, the familiar is not "casting the spell," because familiars do not themselves have spell slots, but the find familiar text says that it delivers the spell "as if it had cast the spell."

Does this mean that casting a spell through a familiar this way means the familiar can be targeted to counterspell the spell, even though the familiar itself is not using the Cast a Spell action, because it's treated as if it was casting the spell?

Or would counterspell only be able to be cast on the person actually expending a spell slot to use the Cast a Spell action, i.e. the wizard itself, not the familiar?

Answer 1

No, counterspell must target the caster casting the spell to be countered, not the familiar through which the spell would be delivered.

The description of find familiar says "your familiar can deliver the spell as if it had cast the spell." The key words here are "as if." The familiar is delivering the spell "as if" it had cast the spell, but that does not mean it actually cast the spell.

Examining the core rulebooks reveals that the designers consistently use "as if" to signal rules of like treatment, not identicalness. For example:

• The darkvision trait permits you to "see in dim light within 60 feet of you as if it were bright light, and in darkness as if it were dim light." (See, e.g., PHB p. 20.) The point is that, for purposes of vision, you receive the treatment you would receive in better lighting -- but the lighting conditions themselves don't change.
• The description of an animated shield says "The shield leaps into the air and hovers in your space to protect you as if you were wielding it, leaving your hands free." In other words, with respect to handedness, you receive the treatment you would receive if you were not wielding the shield: you get to have both hands free to do something else, like wielding a two-handed weapon.
• Within the extraplanar paradise created by a rod of security, each hour "a visitor regains hit points as if it had spent 1 Hit Die" -- but doesn't actually spend a Hit Die. When the visitor leaves, she still has the Hit Dice she came in with. (If it were not so, the value of a rod of security would be rather reduced, since anyone could spend a Hit Die normally by taking a short rest in the same one hour.)

By the same logic, for purposes of delivering the spell your familiar receives the treatment it would receive if it had cast the spell, but it has not actually cast the spell. Counterspell therefore would not be effective if it targeted the familiar rather than you.

Answer 2

I've had to adjudicate this in the past. Counterspell targets the creature casting the spell, to interfere with its casting. Counterspell does not target the delivery mechanism (be it a cat, sword, fang, or bolt). So you have to see the caster (have line of effect) and be within range for Counterspell to work.

I believe the range of 60 ft. here is such that the countering magic user must be able to see the details of what the casting magic user is doing in order to effectively counter it.