An inquest into his death at Surrey Coroner's Court in Woking previously heard from Mr Parker's carer Harry Beckwith, who said he had landed on Mr Parker when he jumped in the pool after him on June 11.
Giving evidence on Tuesday, senior support worker Joanna Henderson - who was on the trip to Salou - told the court she asked Mr Parker, 43, not to jump into the pool when she saw him doing so on June 10.
Mr Beckwith said he then realised Mr Parker was "not there" and had gone "to the bottom" so went down to pick him up before taking him to the stairs of the pool and asking the lifeguard for help.
Asked whether she was satisfied Mr Parker had understood her instructions, Ms Henderson said: "Yes, by the manner in which he came out (of the pool) and stopped what he was doing.".
Ms Henderson told the court she expected The Grange pool rules to apply to the hotel pool for their clients and staff.
