Brandon Blackstock was fighting a difficult cancer battle before his death … but, you could hardly tell a couple weeks ago when he was grinning big in a photo with his daughter.

Savannah Blackstock Lee, Brandon’s daughter from his first marriage to Melissa Ashworth, shared a photo on Facebook last month standing alongside her dad with a sprawling wilderness behind them … and, Brandon’s arm is slung over her shoulder.

Blackstock’s got his Uggs on … bringing his leg up on a bench Captain Morgan-style. Savannah’s totally beaming in the pic — and, from the outside, it seems like nothing’s wrong. She captioned the picture, “Back home to the mountains & my daddy.”

The pic was posted to FB on July 20 — and, Blackstock died early Thursday morning this week after his fight with melanoma.

Blackstock’s ex-wife, Kelly Clarkson, postponed her Las Vegas residency earlier this week to be with her children while Brandon was sick… but, we didn’t know just how sick until Thursday.

BTW … Savannah is expecting her second child — so, her life is full of change right now.

Blackstock was 48.