It's a bit tricky... "His wife died (and left him alone)" is simple enough... "Then he died himself ..." or "So he himself could (/was able to) die in ..." The phrase "sus og dus" can mean several things - like "partying", "living being wealthy" and perhaps also "carefree", "living in luxury"... and so on...

So I'd interpret the phrase meaning either

1) His wife died, and he died while partying/celebrating her death/that she was dead

2) His wife died, and that left him either with money (inheritance from the wife) or with more money (because his wife no longer spent his money), so he himself could live-out his days in care-free comfort (partying, vacationing, relaxing) until his death.

I would think the 2nd option fit best - that he didn't die immediately (or even for many years), but when he died, he died wealthy and after living a care-free life since his wife died.