I wish I had thought of this, but saw it on another board and thought it was a good idea. You could donate to any similar fund, and have the acknowledgement sent to any other pro-gun-at-all-costs group. It is a way to do something positive and make a statement to the group(s) that exert their power and money to keep politicians from doing what needs to be done. It is telling them that there is money and power being sent to fight them.
On days like the last few, it feels good to do something that feels positive.
Of course, I think addressing the mental illness issue is also important, and dare any selfish bigot to challenge the Obamacare spending on mental health now.
Here is the link to the "Contact Us" page at the NRA.
https://contact.nra.org/
Link to the Brady Foundation, which has a statement and a place to leave condolences:
http://www.bradycenter.org/