Advise on house share percentage/ amount legally is my son eligible.

I am a 58 yr old living with my husband (67),Son and Daughter in law. This current house is bought from 75% of my own funds( By selling old house which was completely in my name) and 25 % by son (Bank loan). The new house agreement is jointly my and my sons name. Also approx 15% of proceeds from old house sale are used for house interiors, jewellery & marriage expense of my son. My son and his wife are planning to separate with us. My son and daughter in law are expecting/demanding 50% share of house. According to me, my son is only liable for 25% Amount which he has contributed.