Left A Check For Me In Suicide Note

My ex husband committed suicide. He left a note a check to me for $50,000. We have 2 elementary age children together. I have been given advice to cash the check and put it aside. I am unsure what do. It feels so strange. Do I go into the bank and explain? Do I just hang on to the check? I'm sorry I'm coping by problem solving.

If it's important: There's no will. No power of attorney at this time. Our kids were his only dependents.

Update: Kinda. I haven't fully decided what to do yet. There's a little bit of context here, though probably not entirely legally relevant. I live in California.

I have pictures of the note with the check he left. In the note he clarifies the money is for the kids and I. He has very little debt, just a car loan for less than 10 grand.

His children and I are about a month from being homeless, and this is something he knew. He does have the funds in his account and then some. I believe this is his portion of the house we sold. I believe his intention was to make sure our rent was paid for the next several months, as this was one of our biggest stressors.

I would love to get a lawyer, but at this point we were struggling to afford food and rent. It's clear we will need a lawyer to some degree, though he has no other dependents and his mom wants to make sure his kids and I are taken care of, so I don't imagine there will be much animosity. Can someone guide me how to proceed? Do we have to have a lawyer? Are there low cost options to this? I have informed the military of his death as he was a veteran. They didn't tell me they offered any legal services, just counseling and will help with his pension.

My mother also just died so I'm feeling really overwhelmed in navigating all this. Thanks for any and all legal info.