In Valley Song, the author mentions the things that Buks has lost to make life as "bitter as aloe juice." What are they?

The character of Abraam Jonkers, who most people call "old Buks," is a poor tenant farmer (as his father had been). One of the great losses of his life was the death of his wife after almost a half century of marriage. Years earlier, they lost their daughter. Finding life on the farm stifling, she had sought liveliness and opportunities in Johannesburg but died there when still quite young.
Buks and his wife then raised her daughter, Veronica, who is also on the verge of moving. Abraam's faith and his commitment to living ethically have, to some extent, mitigated the bitterness brought on by these losses. In the play, he is also contemplating his own mortality as well as the projected impact of Veronica's absence.