Is the sale of land included in gross income?

My father earns £15,000 per annum from his job. Back in 2007 he bought a plot of land in Turkey through a re-mortgage via his bank. He has fallen in debt and is selling the land to pay off the mortgage.

The sale will be an overall loss as the land is being sold for almost half the price bought.

My question is, will the sale of land be added on his £15,000 salary on his tax returns? I ask this because my SFE relies on him earning under £21,000 for the support I need through university and if this sale were to push it beyond that it would severely affect my grant and loan to the point where I might have to drop out as my fathers £15,000 cannot maintain me and the house.

Thank you for your help.
Added (1). Update: I didn't mean if he would have to pay tax on the sale - what I meant was would his overall income be classed as £35,000 if he sold the land for example £20,000 (salary + sale of land).

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