So sorry for your loss, Oryxl. This is early days for you, so please do keep on with your counselling. Your grief will take its course, and in time you will feel better, and more able to manage your life.
Your brother is a blessing. And I'm sorry that your children haven't been more supportive to you.
The old saying, 'Time Heals', is true. Well, it doesn't actually heal, but the pain gets less over time, and you will find other things to take your mind off the loss of your husband. You've got to be strong now and 'hang on in there'.
Don't cut yourself off from other people or old friends. These will help you get over your loss, or at least, give you moments of respite from your grief.
And - most importantly - you must get back onto your medical treatment!
And YES, I am sure that there IS life after death. I've had too many experiences of this, not to believe it.
We all have out allotted time here, then we move on. We don't die. We only die from this dimension.
My thoughts are with you. God bless.