You are correct. You did not mention how it came to pass that this person was lodging at your friend's farm--but you mentioned that he has missed 4 months of rent payments--so the lodger apparently does have some agreement with your friend. That being the case, you are correct, your friend will have to use your state's eviction processes. Likely takes 3-5 weeks, sometimes longer and shouldn't require a lawyer--costs will be a bit under $100.
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