2500 ts chassis battery storage advice

[Cuda]

I have put my 2019 ts2500 away for winter, what is the advice for the battery both the house and chassis battery, should I pull or leave them in. Iowa winter . Inside storage facility. I have the coach battery disconnect switch in use. I also wonder what the switch under the hood by the battery does, It is black and red and looks like a circuit breaker or cut off switch , what is this for. Should I pull the batteries for now and charge at home on a trickle . Will the chassis battery drain in 3 months ??

[A32Deuce]

I would just disconnect the ground wires on the batterys. House and chassis as long as they are fully charged. Won't loose much just sitting like that.