Man, there are some watch zealots in here, thinking that a verbal gentleman’s agreement about a collection outweighs $200k in estate property rights. There’s nothing to think about, you have to give them to the wife, right away. Legally, morally, in terms of business-ethics and your reputation, your exposure here is massive.
I’m sorry for your loss.
“He kept his watch collection with me”
“He lets me use the watches”
OP doesn’t claim to own or have been given these watches. They are not his. Purchases made during a marriage are generally considered joint property, purchased with joint funds. The widow inherits the husband’s estate, including all property and applicable debt of that estate. For all we know, the watches were bought on credit, with the debt still owed by the estate.