A Russian soldier is talking about his experience in a KL in WWII as a KG /PW. He was ordered to carry the feed for the people in a barrack, where almost everyone was sick. He says: "Дали мне помощника из этого барака, того, что был посильней. И начали мы носить ....".
I have partly translated: "They gave me an assistant from this barrack, this one that was stronger". But I am not at all OK with this version. посильный means "possible", not the comparative degree "сильнее". Apart from this, it is here like a fem. adjec. Where is the noun qualified? I suppose this is творительный падеж.
Thank you