Ryan Sinclair's mother died of an intense heart attack while doing the washing up when he was thirteen years old, with Ryan being the one to discover her body. People would always tell Ryan that he looked like his mother. (TV: The Tsuranga Conundrum)
After she died, Ryan was raised by his paternal grandmother, Grace, as his father, Aaron, had left him, unable to cope. (TV: The Woman Who Fell to Earth, The Tsuranga Conundrum, Resolution)
By 2018, Ryan had come to theorise that his father avoided him because he reminded him of her. (TV: The Tsuranga Conundrum) Ryan eventually forgave his father for not being there for him after the death of his mother. (TV: Resolution)