I have translated most of the following sentence on my own, but I am having great difficulty in understanding then translating the ending of どうなの.
教え子の名前ぐらい、もう少し考えたらどうなの?
According to nevan king answer at What exactly is "なの" (nano)? ,
The な is only there if you use it after a noun or a na-adjective (きれい, 大変, 非常).
However, as far as I am aware, according to https://dictionary.goo.ne.jp/word/en/どう/#je-52734 and based on the context (shown below), the どう here most likely means "the same". Whether どう is a noun or na-adjective is unknown to me; so I can't accurately use What exactly is "なの" (nano)? to help me understand its meaning.
しかし、アインにツヴァイか……。
教え子の名前ぐらい、もう少し考えたらどうなの?
TDLR: What does どうなの mean in the above sentence?