Desperately in need of legal advice

Tulong naman po. My mom acquire a property and have her sister as the co owner. My mom passed away in 2007. Me and my dad legally married to mom currently reside abroad.We never settle any documents since her death beacause our visit is limited every time we go back. A lot of things change since my moms death. Greed consumed my aunt and her children. My mom allowed her brother(now deceased) and his family reside in my mom share of the property and now my aunt want to get rid of them. They've been residing in the property for more than 30 yrs. Another issue that we came across is that my mom never left us a will. My mom raised me as her biological child and we never talked about my adoption. She showered me with so much love that gives me no room to question instead be thankful and grateful. Mom and dad have me since I was 6 months from my moms other sister. Have both my mom and dad as my birth parents in my birth certificate. We're having a problem right now because my aunt want to sell the property. Can they do that without our signatures?what about the family of my uncle who's been residing in the property for more than 30 yrs. I want to keep the property for sentimental reason, my dad wants me to have it. What would be the necessary steps that should be done. Please help me. Thank you.

Article 493. Each co-owner shall have the full ownership of his part and of the fruits and benefits pertaining thereto, and he may therefore alienate, assign or mortgage it, and even substitute another person in its enjoyment, except when personal rights are involved. But the effect of the alienation or the mortgage, with respect to the co-owners, shall be limited to the portion which may be allotted to him in the division upon the termination of the co-ownership. (399)

eto po