As his new wife has just died he's still hankering about passing on his pension!
I suppose you have already told him to try stop worrying
maybe it’s just something he needs to get of his chest, as he keeps going on about it ,
Sounds like he must have been a proud hard working man (was he? ) Then presume he work hard to provide for the wife , also so if he passes way his wife would have been finically secure with his pension, as she may have not work full time like him .
Back in that day I suppose the benefits where that the wife keep the husband pension when the man passes away as a lot of woman back in those days never use to work ,Must still be the same now.
I suppose that it must be hard to except that his wife pass away first, that’s not going to happen so the government keeps it
I am doing a lot of presuming as I am presuming your FIL is over 65 70 – 80 +