Time for your 18 year old to learn to cook and clean (assuming they are in good health etc)
If you can consider powering through 6 weeks of f/t work then they can step up and get used to practicing these important life skills!
They might surprise you!
You will need nutritious food to support your body.
There's tonnes of prep ahead "dump dinner" ideas online - perfect if you have a slow cooker or instant pot. They literally bulk chop ingredients and put them into zip lock bags and freeze til needed. My 7 and 4 year old make these with me.
Or YouTubers who meal prep a week of meals in an hour or so (I've used downshiftology. that just stay in your fridge.
Alternatively, there are "homemade" meal delivery services - my DD has ME and it's one of the tools we use in a busy week. It's all fresh and just needs microwaved for 3 minutes.
Housework, hopefully if it's just the two of you then housework can be minimal for these weeks as long as they pick up after themselves.
For laundry my DD puts her wash on and I take it out and hang it up. Could be reversed for your family.
Make sure you prioritise connections with friends to help keep you sane! Maybe a phonecall to them while you commute, if that's feasible? Then you can eat and be ready to sleep when you get home? Plan a nice get together after the training is done.
Finally, congratulations on your new job x