It was inevitable in the nature of things.
He apparently accepted the fact as such, and did not attempt to break through it.

He took the strongest interest in other people, and in every thing around him, but he did not seem to expect to have the like returned in any great degree.

Perhaps it was one of those merciful compensations that what he could not have he was made strong enough to do without.
So things went on, without any other variety than an occasional visit from Mr.Menteith or Dr.Hamilton, for seven years, during which the minister's pupil had acquired every possible learning that his teacher could give, and was fast becoming less a scholar than an equal companion and friend--so familiar and dear, that Mr.Cardross, like all who knew him, had long since almost forgotten that the earl was--what he was.

It seemed the most natural thing in the world that he should sit there in his little chair, doing nothing; absolutely passive to all physical things; but interested in every thing and every body, and, whether at the Manse or the Castle, as completely one of the circle as if he took the most active part therein.

Consulted by one, appealed to by another, joked by a third--he was ever ready with a joke--it was only when strangers happened to see him, and were startled by the sight, that his own immediate friends recognized how different he was from other people.
It was one day when he was about nineteen that Helen, coming in to see him with a message from her father, who wanted to speak to him about some parish matters, found Lord Cairnforth deeply meditating over a letter.