It is sad, but we have to remember that this was a different time than today. 80 years old in 1877 would be equivalent to 90 years old or more today. Very few people got to 80 in those days. He lost his wife Margaret less than 4 years earlier from falling down the stairs. If he was at home he likely was the person who found her, which would have been traumatic. On the other hand, we don't know how long he was institutionalized. Maybe Margaret was looking after him, and now there was nobody to do it so he had to be put into a home.
I figure that of their 9 original children, 4 of them might have been alive (Margaret b 1829 wife of Frederick Whorton with a large family, William b 1836 unmarried but always living with a relative, Eleanor (Ellen) b 1838 wife of John Fairclough with a big family at Bolton, and Edward b 1841 who was married to my relative and his cousin Sarah Ellen Gelling and they also had young children). I'm not sure about John b 1826 (can't find after 1851) and Catherine b 1831 (may be the one who married Francis Trappes early 1851 and is in that census, but Francis has a different much younger female living with him in 1861). None of them probably could take on the burden of looking after old Matthias in his later years.
Matthias CALLOW married Margaret GELLING 14 Dec 1819 at Onchan. The first 8 of their children were baptized in the IOM (Douglas or Onchan) and the youngest Edward in Liverpool in 1841.