Yes.
Like many people on a salary, albeit a salary that he worked his butt off to earn, he saved his money and put it into property (and in this case a building company as well).
If he had the skills to build a business, a proper business and not a job, he could have sold the business for 10x profit (the multiple on mid-cap businesses) and, if he had been following me or any good M&A commentator in LinkedIn, he'd have cashed out before the Entrepreneurs' Relief LTL went down to £1m. He (and his wife co-shareholder) would have paid only 10% Entrepreneurs' Relief (now BADR) on £20 million of the capital gains.
On the rest of the money, he'd have benefitted from substantial shareholding exemption as he had set up a holding company and put other structures in place.
And about any capital gains that didn't benefit from all the tax reliefs etc - he could have used that loose change

to buy the freehold on the two sites you mentioned and to start a building company (and to potentially obtain roll-over relief as well).
Or he'd have created an EOT and paid no tax, absolutely zero tax, on the entire capital gains.
Your friend saved money after paying silly PAYE, Employer and Employee NI on part of his
salary and dividend tax on the rest of
the salary, and he invested it. That's what a lot of people who don't own a limited company do. Anybody can do that. It suggests he's frugal and conservative with his money, and he works hard in his job, not that he's a good businessman or that he has built a business.
At any point if he had died, his widow would have had as much luck selling the 'business' as the OP is having. I've seen that sad situation far too often - no succession plan = worthless and unsellable 'business'.
In posting this, I'm hoping to raise awareness among those who've built a job for themselves many of whom think that this is a viable pension plan and that one day they can sell their 'business' for mega bucks. They need to wake up and smell the coffee.
What they THINK that acquirers want is very different to what acquirers actually want.
Take my advice or leave it but it's me out of this thread now.