Family eviction

My husband and myself are my mother in laws durable poa.My sister in law and her husband live in the home with my MIL and she has been very abusive towards her.She was diagnosed with dementia and designated us to be her power of attorney because she knew as time went by it was going to progress and giving her daughter that power would not be in her best interest.We became aware of the abuses a couple months ago after she became ill so we installed cameras for her safety and seen what was going on.They asked my FIL for permission to move in for 6mths till they got back on their feet -that was 10years ago and my father in law has been deceased now for about the 11 years and they have refused to leave .They have never had a written agreement/lease and have never paid rent and occasionally gave money to pay half of the property taxes every other year.My MIL is now having mobility issues and her daughter refuses to help her and has left her stuck in chairs and the toilet and simply refuses to assist her in standing, we call for a wellness check one day and she was transported to the ER due to her vitals being so elevated from trying for over an hour to get herself up.We recently served them with a 3 day notice to vacate 2 weeks ago and they refused to move out and instead sent my husband a cease and desist letter for harassment lol.I requested a civil assist to pick up my MIL wheelchair,medication along with some clothes because we didn’t feel safe letting her return back to the home and upon waiting for the police to assist me in grabbing her things my sister in law informed us her husband changed the locks to the home the day after they were served.My MIL has no access to her home and they’ve have taken down the safety camera in her home and she has not been able to get her healthcare services she was getting at her residence.I went the next day to file an eviction and we have the hearing in a couple days.We did the notice and then petition to evict by ourselves but my husband is worried we should hire and attorney.I have copies of the notice & the police report where it states they admitted to the lock change and the deed listing my mother in law as the sole owner.Should I hire an attorney ?