I just need to know if it is reasonable to say this person was an abusive parent.
This was decades ago btw, the child is now an adult.
Failing to provide adequate clothing, particularly underwear. A typical incident was the child being in top juniors, having to do PE in her underwear and having such big, revealing, holes in her knickers she was too embarrassed to join in.
Not even having a tooth brush. At the age of 12 the child was smart enough to join a dentist herself. She got her first ever tooth brush. She needed 8 fillings.
Not providing a school uniform. At the age of 13 the child got a Saturday job and saved up for months to buy her own uniform.
The child never even had her own bed. She shared a single bed with her sister who was 14 months younger.