These are things the relatives of the friend will have to do:
Here's some context as to what is likely happening:
About Activation Lock on your Apple Watch - Apple Support - https://support.apple.com/HT205009
Here's how the family can resolve it:
How to request access to a deceased family member's Apple accounts - https://support.apple.com/HT208510
Otherwise:
Apple may possibly remove a lock if a person can provide sufficient evidence of valid ownership. The device is normally taken to an Apple Store with identification and the original sales receipt. I.e., the receipt when the item was sold to the first owner, and preferably by that person. There is apparently no set policy (I asked at an Apple Store) and a store may simply refuse, particularly if they are not satisfied you have proven ownership by provenance.