Boys/girls bought for grandson age 10. Now too small for him

Worn a few times but outgrew it quickly. This is meant to be oversized and can be worn for a few years if bought as a long robe to start with

nape of neck to hem at back 74cm 29"

neck at front 65cm 25.5" 

under arm to under arm 70cm 28"

cuff to cuff (laid out flat) 140 cm 55"

width at neck seam 35cm 13.5"(therefore 65-70cm opening for head)  

width at hem 70cm 28"