Parents (Ages 83 & 84) are in a bind w/HELOC

My parents took out a HELOC back in 2015 & extended it in 2020. They’re on a fixed income (~$3100/month). House & car are paid off. I think they originally took out the HELOC for home improvements but as time has gone by, it seems that they’ve also used it to pay for property taxes and lord knows what else. They don’t live a lavish lifestyle; they go out for breakfast (@cheap places $10-20 total) which is their only “luxury”.

They’re now in a real bind due to the interest rate increase. They owe ~$100k and have been paying only the interest. Aside from being bailed out by me, what are their options for relieving the financial strain? What would happen if they just stopped paying?

Edit: Thanks to each and every one of you for your responses and advice!

A few things that were consistently asked/ mentioned:

1. When my parents pass, the house will be sold. I have zero interest in moving there (it’s a nice area, just don’t want to live there). My sibling WILL NOT get the house. I’m executor off their will and will do everything in my power to keep him out.

2. Similar homes in their subdivision have sold for $250-$275k. I don’t necessarily think that’s what theirs would sell for because who knows what the housing market will be like at that time.

3. They live in a low COL area. Their property taxes are ~$3,500/year.

4. Aside from their astronomical cable/internet/landline (🙄) bill, my Mom estimates they spend ~$225/week on groceries. It’s very possible that there was a miscommunication there, since she is very deaf and may not have heard the question correctly because I don’t even spend that much on groceries & we’re big eaters.

5. They’re on Medicare and a supplemental insurance plan. They also have life insurance and long term disability insurance.

6. Their breakfasts out are cheap - $10-20 for both of them (low COL area).

7. They bought a new heater and ac last Spring, new tires for the car, and pay the homeowners insurance with this HELOC money.

8. I’m almost certain they’re not helping out my sibling financially, BUT I’m going to ask them face to face because there were a lot of transactions on their statement (which I went through with them but only picked out the transactions of $500+) for between $200-$400. I truly don’t think they’d lie to me about this, but if I find out they are I’ll be absolutely shattered.