I think the difficulty is that it isn't clear who is actually looking into this matter. The previous care home manager told you that he had been in contact with the safeguarding team and was now speaking with the CQC. The CQC don't have their own safeguarding team, nor do they investigate safeguarding issues, but they do ensure that care homes follow safeguarding guidance to protect residents. If the deputy care home manager has said that she is waiting a reply from the adult safeguarding team that is the local authority, not the CQC. As previously posted, if the local authority safeguarding team decide to investigate the matter they will contact all parties to ensure that they get a full picture of what has been going on. It could be that the care home manager is simply awaiting advice from the safeguarding team with regards to what to do about the situation so there may not be an investigation.
As the CQC have said that the matter needs to be progressed via the care home manager, and the deputy manager has said that she is waiting a reply from the local adult safeguarding team, perhaps it would help to clarify with the deputy manager what exactly the expected reply is in relation to? That will hopefully give you more of an idea with regards to what the safeguarding team's involvement is in this matter, although bear in mind that the covid situation has resulted in delays/reprioritisation of local authority work so that could account for the reason that nothing has been heard in 7 weeks.