Mr Weavall was an old old old man who was seemingly beyond help. Tiffany Aching used to visit him when she was learning witchcraft from Miss Level (both of her...). Amongst the things she hated were clipping his toenails for him (they used to ricochet around the room), and having him grab her arm and ask her to check in the box under his chair, to see if his money was still there. It was.
At least, it was until she was invaded by the Hiver. Under this malign influence she stole the money and used it to buy whatever she wanted.
Once the Hiver had been defeated she went - heavy of heart - to confess, whereupon she was astonished (and ashamed) to find that the Nac Mac Feegle had replaced it with gold from an ancient king's burial site, making Mr Weavall probably the richest man in the entire country.
Galvanised into action, and out of the semi-stupor he lived in, wherein he believed his children Toby and Mary to be alive and well, he came to his senses, was briefly saddened by the fact that his children weren't alive, but then in a deuced hurry to be off down the lane, walking sticks flailing, to the house of old Widow Tussy, whom he immediately proposed to.
Presumably dead by now, but equally presumably he loved every minute of the twilight of his life.