My husband passed away and I do not know his password and I need the phone unlocked

Contact Apple. They need to see a copy of the death certificate and a copy of the will or a document that shows you inherited it.

How to request access to a deceased family member's Apple accounts - Apple Support.    

Apple ID - Official Apple Support.    

Contact Apple for help with Apple ID account security - Apple Support.  (Link doesn’t always load)   

Get Support      Work through the screens to get a chat option. 

Apple Support schedule phone call

https://twitter.com/AppleSupport       People have posted it may take an hour or more to get a response.

Just be aware that Apple will not be able to unlock the phone but they can remove the activation lock so that you can use the iPhone. If you are looking to get information off of his device then Apple won't be able to help you.