You should not rely only on oral submissions before the Court. Oral clarification may not always be properly recorded, and since an incorrect statement has already been reflected in the order sheet, it is important to place the correct position on record through a written filing.

The appropriate course of action is to file a supplementary counter affidavit in person. This is suitable because a counter affidavit has already been filed, and you are only supplementing and clarifying that affidavit rather than replacing it. The issue arises from the same proceedings and factual background, so a supplementary counter affidavit is procedurally correct.

In this filing, your brother should clearly state that he has already filed a counter affidavit in person and continues to rely on it fully. He should also mention that no further counter affidavit is required from his side. It should then be clarified that the statement recorded in the order sheet regarding “re-investigation” is incorrect and appears to have been made due to an inadvertent error. The correct position should be stated clearly, namely that “further investigation” pursuant to the Magistrate’s order is pending, and that this fact has already been mentioned and supported by documents in the earlier counter affidavit.

The language used should remain neutral and respectful, without making allegations against the counsel, and should simply indicate that the earlier submission was made under a mistaken understanding. Your brother should also state that he wishes to withdraw the vakalatnama of the existing counsel and intends to appear in person for the time being.

A prayer may be included requesting the Court to take the supplementary affidavit on record, to treat the earlier counter affidavit as final, and to note the correct position regarding further investigation.

On the next date of hearing, your brother should mention that a supplementary counter affidavit has been filed in person and request that it be taken on record, while briefly clarifying the correction. This ensures that both the written record and oral clarification are aligned.

It is also important to note that the distinction between “further investigation” and “re-investigation” is legally significant, and correcting it at this stage is the correct approach.

It is better to place this in writing, not merely orally. Since a counter affidavit is already on record, your brother should file a short supplementary counter affidavit in person stating that he relies on his earlier in-person counter affidavit, wishes to discharge the present counsel and appear in person for now, and that the correct position is further investigation, not re-investigation. Under the Allahabad High Court Rules, material facts are normally brought before the Court through an application/affidavit by the person having knowledge of those facts.

On the next date, he may also orally mention that this written clarification has been filed and request the Court to read the record accordingly.

If you do not want to continue with the present counsel then you may issue a notice to him informing about the termination of vakaltnama given to him and file the copy of the notice before high court during the next hearing and also file a memo before high court that you have already filed the counter  affidavit that you r advocate had erroneously represented and sought time for filing counter affidavit  which is not maintainable at this stage and express that you are ready to submit your version or arguments as party in person, the high court may hear the same day or it may post the matter to some other day.  . 

2. If you do not want to file additional counter then you can inform the court that there is no additional counter to be filed.

In fact you may not be permitted to file additional counter affidavit without any valid reason because there was n o development after you filed the original counter affidavit i.e., the case is in the same stage hence without leave of court or without any direction by court instructing you to file additional counter affidavit, if any, you canot file an additional counter affidavit. 

Since you have already appeared as party in person and no as you have terminated the vakalatnama given to a counsel, you can continue to appear as party ion person in further proceedings. 

It should be in writing with affidavit 

He should appear in person (if he has not engaged a new lawyer) and inform the court that he is taking over the representation. He should reiterate his satisfaction with the first affidavit and state that the second filing is intended only to correct the record and remove the previous couns

2)To correct the record and withdraw the counsel in the Allahabad High Court, your brother should immediately file a written Application for Withdrawal of Counsel along with a Supplementary Affidavit in Person. This approach formalizes the correction, ensures the "further investigation" status is documented, and allows him to rely solely on his initial affidavit. 

According to Allahabad High Court practice, to file additional documents or facts via a Supplementary Affidavit/Supplementary Counter Affidavit, you must file an accompanying Interlocutory Application (IA) or a "prayer clause" asking the court to "take the same on record"

2)Filing such an affidavit without leave (prior permission) can lead to the document being rejected as it undermines procedural discipline.

You can file an affidavit after seeking permission from court 

In my opinion you have no reason to file a counter affidavit that too under the given circumstances. Since you are going to appear as party in person and that you have already filed a counter affidavit as party in person,  it is suggested that you file a memo before high court intimating your decision to terminate the services of the advocate and request court to continue the case as party in person and you can additionally state that you have already filed counter affidavit. 

The court will record your memo and pass suitable orders.