She will have some teachers pension and the state pension, but there are so many variables its impossible to give an accurate figure. Might she also be receiving a widows pension from your DF?
Any time she was in receipt of CB she would have had NI credits towards her state pension, so she'll probably get close to a full state pension although due to her age it was probably the older slightly smaller amount.
What is more relevant is how she manages her money, and what her fixed costs are. My DM is also a widowed pensioner who probably has less coming in than yours as she never worked full time or had her own pension, she just has the state pension and a small widows pension from my dad's manual worker's pension. She's reasonably comfortable but doesn't smoke or spend lavishly. But she has pets, puts the heating on when she wants, gets her shopping from Ocado, is able to get her hair done, pay for work on the house, treat grandchildren, eat out a couple of times a month, that sort of thing.
When you say your DM 'took out her state pension' do you mean 'opted out'?
Also what is 'sold all her equity'? Are you saying she released the equity from her home and has spent it? Was this a standard remortgage where she has to make payments or an equity release product that doesn't have payments but will need to be repaid when her home is sold?
On paper it's very likely she has enough to cover the basics and a decent amount of discretionary spending but obviously if she smokes, is generally spendy, has loads of subscriptions, has sleepwalked into high insurance costs by never shopping around, is running a family sized house on a single lowish income or endless other factors, then it can be easy to run out of money. But without sight of what is going in and out of her bank accounts it's impossible to say.
She needs to review everything systematically.
Can you get her to look at the Moneysavingexpert budgeting advice?
https://www.moneysavingexpert.com/family/money-help/
Perhaps go through it with her if she's struggling to work things out or doesn't come up with any constructive solutions?