Siblings in houses are definitely a problem. Apparently if he isn't leaving it is likely because he doesn't have any money to do so. If the estate has some cash perhaps you can give him an advance against his share of the estate.
Otherwise, if you are going to evict him you must follow the rules and, likely, it makes the most sense to retain an attorney for that purpose.
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This appears to be a duplicate of your earlier post. The executor is legally authorized to take this action for the estate. I would let him or her do so and that keeps YOU and your other siblings out of the fray.
This is a matter for the courts to handle, now.
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The executor has the legal authority to get an eviction order and have local police help execute the order.
The answer given does not imply that an attorney-client relationship has been established and your best course of action is to have legal representation in this matter.