OP you are refusing to help yourself.
Take a look at the criteria for PIP. Take a look at your award letter for the reasons you've been awarded it. If those reasons are incorrect ie if you've been given 2 points because you can do xyz but actually you can't do xyz and should have 8 points, then you need to get your PIP claim looked at again. Report a change of circumstances to say it's worsened from whatever they say the situation is, if they've got the situation wrong. Because if you're not getting the correct amount it's because they haven't given you the correct acknowledgement of your issues. It can be sorted.
Your husband needs to apply. He can get the ball rolling with a claim and seek out the paperwork needed later. It takes time for the claim to progress.
If your CAB is never open then phone them! They'll have a system for making an appointment. Use it.
Talk to your children. You have at least one son, the one with a family, who can most likely afford an extra large tin of peas and potatoes and an extra chicken to feed a few more people, he's the one who is best placed to host your family Christmas this year. Your children would much rather learn of your hardships and have a bit of worry about that than be told of your deaths from hypothermia or starvation.
Refusing to do all the above is an example of the twisted illogical thinking I was talking about. You literally can't think straight when your brain is starved of fuel. I'm also wondering if any of your health symptoms are actually caused by malnutrition or being exacerbated by it. Because on two meals a week you are most definitely malnourished.
Are you working OP? If not, is it because you're fit for work but currently unemployed? Or is it due to your health? If you can't work for health reasons you should have a Low Capability for Work Related Activity on your UC claim, but you have to claim this and jump through their hoops to get it. So if you're supposed to be getting that then claim it. It gives extra money per month.
You should look into claiming council tax credit too, that's not included in UC. You have to claim it separately, it's for people on a low income, regardless of where that income comes from.