[Legal/Inheritance/Marriage/HK] Enforcability of a will bequeathing to children vs. seperated spouse

Hi there,

I am currently (de facto) seperated with my expat husband for over 7 years, and he lives with his new partner in mainland china, but we are still legally married and have children past adult age. We both have our own sources of income to support ourselves independently, however it is not clear what is the ratio of assets between us (possibly I have more given that my husband's assets are shared with his partner).

My brother would like to gift a residential flat in HK to me but is unwilling to commit until he has clarity on the legal situation regarding the future ownership of this property if I die before my husband. Basically he is reluctant to see the property fall into the hands of my husband in any eventuality. He would rather it be interited by our children.

My question is, if I draft a will to bequeath all assets (including this flat) under my sole name to our children, is there any legal recourse that my husband can take to gain a share of these assets?