I'd fill the tank and add some Power Service additive.
You don't need to remove the battery if you can connect a charger to it. What I did when we moved to Singapore for the first time for 9 months was to remove the battery from my Benz diesel, took it to the basement and connected a trickle charger through to 110v through 2 of those simple 24 hour timers in series. Think I had each timer running approximately the minimum time; think this is roughly 1-2 hours.
When we returned, I put the battery back into the car, got in, pulled out the glow lever (one of those old fashioned ones) for 30 seconds or so, turned the key to start. It started immediately.
Back in those days, I'd never heard of diesel fuel addition. Just left it with a reasonably full tank in the garage. Never did use any additive in that old 1973. Have had to use Chevron Red Line twice in my 1983, to eliminate diesel ping at constant speed.
Ralph