As I understand it, wrongly or not, temperatures in the sun's outer layers are about 6000K as opposed to the upwards of 100,000K ablative temperature of a heat shield during aerobraking.
The relevant temperature is not the temperature of the star's atmosphere, it's the temperature to which everything is heated by friction.
If you compare 0.1c with the kinds of velocities we have for interplanetary probes (roughly on the order of magnitude of escape velocity from the solar system), it's about 100 times greater. When you increase the velocity by a factor of 100, you increase the kinetic energy by a factor of $10^4$.
A second huge factor working against you is that the time is very short. The distance over which your probe has to stop is at most on the order of the diameter of the star, and in reality it's going to be a lot less, since you don't have any way to curve your trajectory to match the curvature of the star. (If you had a way to curve your trajectory like that, it would require a large acceleration, which is what we're trying to accomplish in the first place.) Even taking the stopping distance optimistically to be the diameter of the sun, the time to stop comes out to about 20 seconds, which is extremely short.
So you have the combination of these two factors: a huge amount of heat being dissipated, and a short time to get rid of the heat. This is a huge amount of power, and convection simply isn't going to be a fast enough process to get rid of it. If you want to make the maneuver work, you're going to need some exotic and extremely efficient method of getting rid of the heat.
would using this method of deceleration be in some way more attractive than an aerobraking or magnetoshell aerocapture around a planet
Yes. The diameter of the sun is about 100 times greater than the diameter of the earth, or 10 times the diameter of a gas giant. That means that the time considerations get much worse if you try to brake using a planet's atmosphere rather than a star's. By the same logic, a supergiant star would probably be better than a main-sequence star like the sun.
Plot synopsis: a ship traveling at sub-light speed is too low on fuel to decelerate in time to keep from blowing through and past its target solar system. Radical measures are considered.
This makes it sound like you have in mind a crewed ship. To get from 0.1c to rest in a distance equal to the diameter of the sun, you would need a deceleration of 30,000 gees. That would kill the crew.