having spent some time with an epileptic and having witnessed a
few seizures, it's clear to me that recovery from a big epileptic
seizure is not instant. The senses return slowly, particularly the
sense of where you are and what you were doing

Having lived with an epileptic for about half a year, my experience
matches yours. Recovery from a seizure is anything but instantaneous.
It can take several seconds, or several minutes, or longer. There is
no real consistency. There is invariably a period when the epileptic
is conscious and aware, but not all there - still in a mental fog.
There is also a learned response to curtail action until full mental
acuity returns - but I imagine this is a learned response, not
something one instinctively learns after the first seizure.

In other words - I agree with the other poster. The pilot likely acted
in a mental fog. He was in the mental fog through no fault of his own,
and could not possibly be expected to know that his mental faculties
were diminished at the moment. He is certainly not to blame.

Having said that - I think that it is absolutely legitimate to question
whether he took the correct action (remembering always that if he did
not, he can't possibly be faulted for this given his condition).
However, I'm not all that certain his action was incorrect, even if his
reasons are specious.

no desire to proceed any further into marginal weather

I can't see that the weather was an issue here - bases at 2000, 2-5 in
haze might be marginal VFR - but it's easy IFR by anyone's definition,
and he was on an IFR flight plan.

concern over the loss of altitude;

1700 ft isn't terribly high, but it's not low either and that plane
climbs quite well especially with only one aboard. He could have been
back at his assigned altitude of 3000 in 2 minutes of cruise climb or 1
minute in a maximum performance climb.

concern that the plane's structural integrity was compromised by the
high speed descent and recovery

Concern regarding the structural integrity of the plane is misplaced -
a momentary overspeed without significant overgee, without the violent
shaking that would accompany flutter, and without any indication of
control problems certainly does not call for parachute activation.

and concern that the weakness in my
right leg might hinder my ability to control the plane down to the
runway

The Cirrus doesn't need much rudder - even a no-rudder landing,
assuming no significant crosswind, would most likely mean no damage -
and certainly no injury.

However, the very quality of the reasoning argues for diminished mental
capacity. Also note that there were only three things he had to do for
a proper parachute activation - reduce airspeed below 130 kts, shut
down the engine, and pull the handle. He got one out of three right.
If that's as well as he was going to do, how well was he going to do
for the next few minutes of flight? Sure, he got better - but he
didn't know he was going to get better. He could have gotten worse.

As it happened, not shutting down the engine served him well - he was
able to use it for steering - but that was luck. It was also luck that
he recovered enough to do this. Had he taken minutes rather than
seconds to recover sufficiently (and I can assure you I've seen
recoveries from even mild epileptic seizures take that long) he might
have gotten himself killed. Had he had another seizure (and I've seen
a relatively brief and mild seizure followed by a minute or so of
relative lucidity followed by a much more prolonged and severe seizure)
he would certainly have been better off under parachute.

What I really have a problem understanding is not the people who say
the pilot is not at fault (I agree) nor the people who say that given
his medical condition, activation made sense (I agree), but the ones
who are somehow trying to claim the reasons he gives are valid, rather
than the result of diminished mental capacity at the time the decision
was made.

Michael