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First, thank you and your husband for your service.
Second, I am amazed a battery made it 6 years. I've never had one go past 4. The silver lining here is that the battery was going to go out, either on you or him. Now, he gets to come home to a clean and well taken care of car. I'd be happy with that if my fiancée did the same for me (though she doesn't like driving my "big car".)
Since Christmas is covered, when Valentines Day/Anniversary/Birthday comes around, get your cars a jump start box. A good one can be found for around $100 and easily store in the car. Never rely on another vehicle to jump you again. I have a NOCO GB50 which is a bit costlier, but can start a diesel (DT466) in freezing weather.
I recommend this one. https://www.amazon.com/NOCO-GB50-UltraSafe-Lithium-Gasoline/dp/B07MVY7K43/ref=sr_1_9?keywords=jump+box&qid=1647542434&sr=8-9 A dealer who I see sometimes has one and it provides long continuous good amperage voltage. I bought a 100 dollar one from costco and it drains too fast for how heavy it is, plus lead acid cells degrade probably twice as fast.
I've never started the dead vehicle while the donor was still connected. That's not necessary, and doing so can actually damage the battery of the donor or even the more expensive electronic systems in the donor vehicle.
You start the donor vehicle, leave the dead vehicle OFF, keep it running for 5-15 minutes. Disconnect the donor, and start the dead vehicle.
If it doesn't start, turn off dead vehicle (key accessory, door closed, interior lights off, etc.) and repeat.
NEVER start the dead vehicle while the donor vehicle is still attached.
Better yet, get a NOCO Boost jump starter and don't worry about keeping jumper cables in your vehicle or damaging either vehicle's battery or electrical system.
Do you think something like this would have enough power to do so? NOCO Boost XL GB50 1500 Amp 12-Volt UltraSafe Portable Lithium Jump Starter Box, Car Battery Booster Pack, And Heavy Duty Jumper Cables For Up To 7-Liter Gasoline And 4-Liter Diesel Engines https://www.amazon.ca/dp/B07MVY7K43/ref=cm_sw_r_cp_api_glt_i_4335Y2YG3JR9X3J3GBAX
Yea I bought one of these and it has been useful a handful of times. I've only had to jump my 2020 RAV4 once with it but I have been in random times where strangers are wanting a jump and I have pulled this out to save the day.
There are battery packs such as this which plug into your 12v power outlet (or cigarette lighter outlet as it used to be reffered to) which can jump start your own car.