Battery/ generator/ converter issue

UPDATE:
Had to get jump to start starter batt. Totally dead. Took a long time. Not enough juice to keep it running for long. Under hood I found even another wire disconnected (wire #3) this one looks Like it’s going from a small relay to ?

kimberlysmoore wrote:
Finally got rid of the shady mobile mechanic who was making things a mess under my hood.
My generator was running fine for a few days. All dash readers good, all batt indicators reading fine.
Then mech said 1 6v house battery was dead. Wanted to “take it off my hands”. I say “that’s ok, I get a core charge with new purchase”.
Taken to Napa to be tested as “fine”. Topped off with a charge.
Mech reinstalled.
Now dash battery indicator reading red (almost dead). Small dewalt inverter plugged into cig lighter reads red (not enough juice to charge 110 for laptop). Plug in several usb power boxes to charge.. all seams well.
Still dash batt indicator said red.
Go out to look at things for myself.
1 wire just hanging there...? I ask mech “where’s this go?” Mech said “I don’t know but if you can charge a usb who cares. Leave well enough alone”. Wtf?
Put wire on batt terminal, dash indicator reads yellow (halfway there). Follow wire, appears to be gene attached but not 100% sure.
Start RV to charge batt. Leave running for several hours on yellow (Don’t yell at me...This works for my RV in the past. I’m boondocked with no shore power and rear end mechanical issues). Come back to a red dash light again. In the past, this would be green by now. Unable to start generator, Batt sounds dead. It’s trying to turn over but no power.
Mech goes out to look at gene and see what is the issue. Tells me “some wire just disintegrated in my hand”. Now gene isn’t running anymore at all (???)).
I tell mech to please stop touching stuff.
He leaves in a huff. try to find wire that has “disintegrated” but can not see what he’s talking about. I start looking for my multimeter, the attachments are missing, my drill is gone, my impact drill is gone, my batts for dewalt drill set and charger are gone. Mech has ripped me off. His phone is going to voicemail.

In conclusion: for 2 days now, inverter On cig lighter will charge small power banks via usb output, non stop but stays red. Pretty sure this is drawing power from starter batt but not sure.
Dash battery indicator still red for house batts. Green for starter batt.
Gene tried to start but not enough juice.
Need to either buy new multimeter it’s find connectors. Ugh.