Repairing wool socks

Below is apicture of socks that I obviously love-wool worsted. someone earlier suggested how I could attempt to repair them. I’m wondering if I could use 2 strands of yarn in the heel area so they would, hopefully, last a little longer. Any ideas?

Why not give it a go? You’ve got nothing to lose, right? Some ready-mades have double thick soles!

I’d use something that’s got nylon in it for a bit more strength & wear.

Good Luck!