He should have shot them both in the legs and claimed the gun went off (er, twice) when he fell down the stairs. That way he would have had some form of defence and these thieving bastards might have had the rest of their lives to consider the error of their ways from the comfort of a wheelchair.
The only thing I can see wrong with this scenario is that the taxpayer would then be footing the bill for the rest of their days however given the cost of having them lose in society (or banged up from time to time) I think I could live with it.
I'm not a raving right winger, just someone who is sick of seeing scumbags living off decent members of society rather than going out and making an honest living. In my previous career I used to see upward of a dozen people a week who had been burgled. The sight of elderly people too scared to open their doors when they should be relaxing and enjoying their retirement is not something I enjoyed.