ANSWER:

Ask him to provide an authentic hadith where it is mentioned that you need to do Istinja after passing wind to renew the wudu! 

He will not be able to produce this as what he says is not authentic. 

Performing istinja from passing wind is an innovation and it is done only by Shia to my knowledge of yemen, known as azzaidiya.

https://islamqa.info/en/answers/2137/istinjaa-for-breaking-wind

Is there a hadith to say we do not need to do istinja if we have let wind out and only wudhu is needed because my husband said he hasn’t seen a hadith on this and only opinions of speakers to say only wudhu is needed. So everytime he lets wind out he does istinja and then wudhu. Could you clarify this please ?

Ablution (Wudhu) | August 20, 2019 5:42 am
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sheikh, for wudu when one is wiping their ears does the water have to completely touch the whole inner ear section bit I find that somtimes I am wiping round a couple of times so that I can ensure that the water has touched everywhere but because it is meant to just be a wipe, is it obligatory to ensure it has been covered completely or is it whatever with one wipe covers?