You have five children, and I feel like you need to remind these adults of that!
You don’t have to explain your finances to anyone, least of all grabby, selfish adult offspring.
You will need your money for yours and husband's needs in later life! Also, what are the tax implications of doing this, and how would you safeguard what’s left once you die? And I really feel like these adults offspring would contest any Will you made!
I recall a recent thread about Wills and how in Scotland you can’t disinherit people? I think you need legal and financial advice around this.
Where are your other 2 daughters with special needs? I presume they don’t live at home, as you don’t mention them and a 2 bed place would be too small I think for 4 adults.
If your adult male offspring want to have such a large sum of money from you, perhaps remind them, that you and your husband worked to save a deposit and pay off a mortgage, but that if they wanted to each pay the equivalent of 50% of the mortgage and interest for the 25 years or whatever, that you held a mortgage, you would be more than happy to give them the money from the sale. Because, that’s the only real way that people make money from property, they work hard, save a deposit and pay a mortgage off! These two want all the profit without the hard work!