Rental apartment with extreme mold.

I am renting an apartment in Amsterdam since April 2021 and living there with my husband and two children. Already in fall 2021 we had a slight mold problem. Landlord advised to clean and spray and ventilate well and keep the heat up. And said there is nothing else that can be done. Mold came back in the same room (bedroom) and also in the living room behind couch but this time very extreme. We did not know for a while but my husband started having health problems with his asthma. Went into emergency room and hospital once end of January. Then we discovered the mold last week and after I cleaned it he again had a life-threatening asthma attack. Was hospitalized for 5 days and doctors in germany tested for allergies and found allergy to mold. I contacted landlord and they said they will come 16.3. with a constructor to check the situation. We are currently still in germany staying with family because my husband cannot return to this apartment. I don’t believe the mold problem can be fixed by spraying or painting walls, since as the landlord already said as well (in 2021) that the moisture is in the walls to the outside because it is an old building and not enough insulation. I wanted to ask advice about what we can do, I assume the landlord will just suggest painting wall and cleaning and ventilation but it is not safe for me, my husband and children to live there. Do you think you can help me with this? I would really appreciate to hear from you.