My husband and I have an LLC. He died and I am the surviving single member. Should I file Form 1065 as a final return with a single member? When should I file form 8832.

Sorry for your loss,

Yes, you should file a Final Partnership Return Form 1065 and be sure to indicate 'Final Return'.  The IRS will automatically downgrade the partnership to a Sole Proprietorship, so you don't need Form 8832, unless you want to be treated as a Corporation. 

You will be able to file your business on Schedule C in your personal tax return next year.

If you still need an EIN, you'll have to apply for a new one for yourself.

Here's more info:

https://www.nolo.com/legal-encyclopedia/does-single-member-llc-need-ein.html