Donna-demo...

[Tsurugi]

Can somebody explain me how to use negative form of copula(de wa nai) after donna-demo form?

For example, could I say-Kare wa donna isha demo nai(arimasen)?(He is not any kind of doctor).

[Damicci]

I tried searching for a bit but it seems that ではありません can not come after どんな～でもwith out a verb or something.

I couldn't find any instance of どんな～でもではありません　Or　ではない・どんな～でもない。
The statement itself seems to not be able to become negative.

どんな善でも人の善は偽善ではありません　I find sentences like this.
donna zen demo hito no zen ha gizen de wa arimasen.
No matter the kind virtue a person's virtue will not be hypocrisy.

So どんな～でも is more like "no matter the kind of ~" than "any kind of ~"

But still I could be wrong I don't have any native speaker to ask about this right now.

[ASHIKAGA]

Here's a couple of examples.

(Watashi ha) donna ni mazui ryouri demo, tsuma ga tsukutta mono de areba kesshite monku ha iimasen.

No matter how terrible the dish, if it was cooked by my wife, I would never complain.

Kanojo ga donna doryokuka demo, itsuka orinpikku ni derareru to ha gagirimasen.

It doesn't matter how much of a hard worker she is, there is no guarantee that she will one day be able to compete in the olympics.

Kodomo wo sodateru no ha totemo taihen na shigotodesu. Donna hito demo ii oya ninareru wake deha arimasen.

Raising a child is a hard work. Not everyone can become a good parent.