WO2 John Smillie, from Crewkerne, and his wife Sarah had previously visited the charity run by founder Lilias Ahmeira and her staff and volunteers.
Special Horses for Special Children offers sensory therapy, horseplay and riding with tricks to families with children on the autistic spectrum or who are suffering emotional trauma or neurological problems.
The couple’s son, Thomas, who had been displaying some degree of social withdrawal, had a session at the centre, which prompted his father to hold a Christmas raffle, which raised £150, and officers proposed and approved a further £250.
John and Sarah, along with their son and daughter, Betty, went to the centre over the festive season to present the cheque to Lilias.
She thanked the Smillie family and everyone at 40 Commando for their help and donation.
Lilias said: “Special Horses for Special Children is the only facility of its kind in the country.
“Families have been travelling from as far as Birmingham, Wales and Surrey for its help.
“The ethos of involving all the family members and allowing buried emotions to come to the surface reaps benefits to parents who are strung out, as well as the children with issues they are coping with.”
Plans are in the pipeline at the centre to offer therapy for adults with mental trauma, bereavement and families with anxiety separation issues.