Prostrate cancer incurable st4 T1N1

My partner was diagnosed June last year.  He’s taking the hormone therapy and we see the radiotherapy consultant in 2 weeks.  Since June he has become soo very tired and now he’s getting breathless walking up stairs.  Plus his feet and legs hurt.  We live apart he has a 21 year old still at home and has his grandkids every other weekend.  Tbh this suits us perfectly as we both get free time.  He is the kindest loveliest man I have ever met.  I love him dearly.  I’m really struggling thinking about what’s to come.  My dad had an awful time with this disease - but he gave up.  Reg will fight all the way.  I’m not sleeping and I’m very teary when he’s not here I will take him to all appointments and he’s going to come here for longer breaks.  I just want to be the best I can for him and try and get out of this awful feeling of dread hanging over me.  I’ve read it might be anticipary grief but I need to be positive.  Has anyone found ways to overcome this? Sorry to ramble xx

ps:  we laugh all the time when together I think I’m just fearful when he’s not here with me?!  Laughing is a great tonic I know