I'm curious about conditions of a will

About 10 years ago, my brother-in-law used an online site to create a will for his mother. He made my husband the executor, and me if he was unable. The b-i-l lives in another state and we lived close to his Mom. When my b-i-l made the will my m-i-l was living independently. She was in an apartment that was in our town, and my husband and I provided basic furnishings, such as couch, chairs, tables, bed, and dresser. About 2 years after the will was created, she went to a nursing home for dementia. My husband and I packed her apartment. There is another sibling involved, who lived near, but wasn't close to the family. We communicated to that part of the family that we were packing the apartment and gave them time to come and get anything they wanted back that they had provided or gifted her. After that, we moved the remaining items to our house and have stored them since about 2014. My husband passed away about 5 months before my m-i-l. I took over as her executor, and settled her estate after she died. There was very little actual assets, and I dispersed them according to the conditions in the will. I had read through the will when my b-i-l had set it up, but I didn't realize we would be m-i-l's main caretakers, that my husband would get sick and die before his Mom, and other life events. It turned out that my husband inherited her personal property, and if he was deceased, it went to the sibling. Most of the boxes were intact, but the b-i-l who wrote the will went through the photographs and took many. I let him because whenever he visited his Mom, she always let him take any photos he wanted. Other than the photos, I didn't give away anything at the time. The sibling contacted me through email and said the conditions of the will meant that they got m-i-l's possessions. Then turned around and said they didn't want them. That was almost 5 years ago. I moved my m-i-l's boxes to the back of the basement, and left them there. I also stored a few things in a closet to keep them nice. The sibling has contacted me recently and has decided they want their mother's possessions. I hope they actually get them. Last year, I gave 2 pictures stored in the closet to my daughter. The pictures had been given to m-i-l by her nephew, and after 4 years, I thought they may as well be given to a family member. I am not going to mention those to the sibling, unless they ask.

I just got to wondering who actually has owned the possessions during the time they were stored in our house, before m-i-l passed away and in the years since? I don't want the possessions, and if the sibling wants the 2 pictures, I can get them back. I did wait for over 4 years before giving the pictures and that was 4 years after the sibling said they didn't want the stuff. Two years ago, the sibling moved over 1000 miles away, but has returned to my area. You can bet I thought those boxes were staying in my basement forever.

I tried to google this, but it is hard to frame a decent search, so I thought I'd post on DU and hear opinions. It is cut and dried, in that if the sibling shows up to get the stuff, I'm not changing my mind. The post is really just a way to fill some time.