Ref. No. 41/1046
In the name of Allah the most gracious the most merciful
The answer to your question is as follows:
Coat-pant is not an un-Islamic dress. The pant-shirt or coat, in which the contour of body parts is not exposed and the structure of the hidden parts is not revealed, will not be called an un-Islamic dress.
If he conveys Islamic rulings in the light of authentic research done by Ulama-e-Haq then there is nothing wrong. However, a Muslim should always keep on wearing the dress of pious persons.
And Allah knows best
Darul Uloom Waqf Deoband