I would put a comma before "who". Otherwise the English looks fine, but more context is needed to fully establish that "assist" is the right word.
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ronieldeguzmantanks, so what should be the right term to substitute the word 'assist' to this sentence."assist" may be correct. It is not possible to know for sure, or to make any other suggestion, without knowing more about what you will be doing for your father-in-law.