Les soucis de santé pour son fils Eric conduisirent Fiebig à effectuer deux séjours à la montagne, l'un en 1925 à Ladevèze, l'autre en 1926 à Lescar.
La description des symptômes de la maladie de son frère par Raya Fiebig, fait penser à la mucoviscidose.
Durant ces séjours, il s'occupera tendrement des enfants Raya et Eric qui furent au cœur de son inspiration. Leur accoutrement vestimentaire est la marque du centre aéré de Ladevèze.
|The poor health of his son Eric led Fiebig to stay in the mountains on two occasions, the first one in Ladevèze in 1925, and the other in Lescar in 1926. The way in which Raya Fiebig described the symptoms of her brother would lead us to believe that he was suffering from cystic fibrosis. During these trips, Fiebig looked after his children Raya and Eric with tender care and they were the source of his inspiration. Their clothing, which was partially provided by the activity centre of Ladevèze, was characteristic of the centre.|