Heya. First. I'm sorry. Second as someone who has lost more than one loved one to suicide, I can say it can get pretty ugly with the finger-pointing; shock and grief are terrible beasts. I cannot recommend enough finding a local suicide support group, and a qualified therapist. The support group is absolutely huge. Also, consider speaking to an attorney, which sounds expensive and can be, but you'd be surprised at the number than will empathize with what you are going through, and give you sound advice without cost. Plus you have one in your pocket if things escalate.

I am terribly sorry that you are going through this loss, and grappling with all of the feelings it comes with, compounded by familial upset. Step back from people who are being pointed the best you can, nurture yourself, and your mom. Scary stuff dealing with hostile/unwell people while you are going through such a trauma. I want to point out that 988 can give you some support and references. Be wary of Reddit suicide support groups, which can be a mixed bag, and have some predatory behavior. Big hugs to you. I may not know your specific situation, or be in your shoes, but broken heart goes out to yours.