Also the fact that it seems no one from his work (bosses or colleagues) phoned him or made contact in his absence to enquire about his or his mother's wellbeing

Also the fact that it seems no one from his work (bosses or colleagues) phoned him or made contact in his absence to enquire about his or his mother's wellbeing to empathise with him on his resignation (which would have therefore eliminated his "surprise" on his return.