This plant belongs to dendrobium section latouria.
So you can look up information regarding its care.
Basically bright light, warm, lots of water while growing. These plants are known for super long lasting flowers.
It looks to me the yellowing flowers are just wilting because it's about time.
Given the super wrinkly canes on your plant, I think you need to either check the roots for any rot, and/or if the roots are good, then up the watering.
Sever underwatering also causes premature flower drop.
Happy Growing!