Hi and welcome to Just Answer!
Sorry for your loss.
Unfortunately the deadline for claiming a refund has run out...
The statute of limitation is tree years.
Thus - the statute of limitation to claim a refund for 2009 started on Apr 15, 2010 when the tax return was due and run out n Apr 15, 2013...
That means - even you are due a refund for 2009 - because of that statute of limitation the IRS will not issue a refund check and will not consider that refund toward your tax liability for following years.
Sorry for bad news.
Unfortunately - it is too late to claim that refund.
Similarly - you would not receive any refund for 2008.
For 2010 - as you have the tax liability - that liability will be in effect. You may ask the IRS to abate penalties, however there should be a reasonable cause to have the abatement approved. I think that the death of your child may be used as a reasonable cause. However - the tax liability and interest charges may not be abated.
You may either use a form or may attach a note (better type instead of hand written). File a form 843 -http://www.irs.gov/pub/irs-pdf/f843.pdf to request the "accuracy related penalty" be abate based on reasonable cause. If you provide the reason like "I forgot" - I do not think it will be considered as reasonable - so be careful when prepare an abatement request.
Here are instructions - http://www.irs.gov/pub/irs-pdf/i843.pdf
If the IRS accepts your reasons as reasonable - and agrees to abate penalties - at least part of the issue would be resolved.
Let me know if you need any help.