Consoling a Mom

My brothers SIL had a 20yo son pass away in Dec from a drug overdose.  I went to the wake although it was very hard and I dont know that I was any help to her at the time.  She was also handling everything as best she could and probably doesnt remember much of anything that went on during this period of time either.  A week before this, one of my children also had a classmate and a teammate commit suicide by hanging.  I know no matter how hard all of this was on me, I cant imagine what she was/is going through and I still ache when I think about her.  

Because I wanted to let her know I was still thinking about her, I sent her a card about a month or two after.  I dont even remember what I wrote in the card.  My brother works with his SIL and sees her everyday.  She has not handled this well at all.  I dont know how anyone could.   

My brother just let me know that my card meant the world to her and that it was more than any of her five siblings have done.  My brother thought it would be a good idea for me to send her another card since she is still having a hard time and I have already picked one up.  I am not much of a writer although my brother said whatever I wrote had touched her.  I honestly dont know what to say this time, but I do think about her often.   

I dont want to repeat myself from the first card, but I dont remember what I said.  Im sure it was along the lines of that I was thinking of her and her other two boys, but nothing about that I knew what she was going through since I have never lost a child.    

Does anyone have any advice as to what I can add to this card for this grieving mom?  We always talked at the family gatherings my brother and her sister held.