Pray for the dead and never assume anyone is in Hell.
However, to answer your question, you really have to look examine it closely. Can you be happy without your mother and brother? I know the quick, gut reaction is to say no, we couldn’t, but let’s examine that.
What is the source of our happiness?
Is it our mother? Is it our brothers or sisters? No.
Our source of happiness is God. We were literally created to spend eternity with Him. That is why we exist. Now, the presence of our mother and brother may make that eternity with God even better, but the fact of the matter is that if we make it to Heaven we will be enjoying the very meaning of our existence. There is no way not to be happy doing that.
What’s more. After the second coming and the general judgment (if not before), we will know and understand the why of each person’s damnation, and we will understand that they chose to be there. We will pity them in so far as we are able to, but in the end it won’t prevent us from embracing God and enjoying the joy of forever with Him.
That’s if we make it, of course. Let’s also not presume our own salvation.