How to extensions in CA. work in regards to filing this year 2023 and things like K-1 forms?

So, my brother is a Successor Trustee of our family Trust that closed out pretty much in 2022. My father passed in August 2021. The Trust was pretty much a house sale. He already paid me my portion of the Trust. 

 

Now I am waiting for a K-1 form that is generated from a 1041 form he must file. I am confused as to when he has to get this to me. I have been told different things. I read on one post the deadline for these type of forms are March 15? I can't file my taxes without this form. 

 

The new deadline is May 15 because of the weather crisis and flooding in CA. where I live. But, now I hear it is in October? Would that be for this type of filing as well? I talked to the IRS and they said he had until this May 15 to file the 1041 form and if he did that I would be required to actually file for an extension to do my taxes this year. I am really confused ball of this. Help?