His tail - looks like fin rot to me. You can treat this like this:
Tail rot or fin rot
•Symptoms: Betta’s fins and/or tail seem to be getting shorter and shorter or they seem to be falling apart and dissolving, Black or red along the edge of the betta’s fins/tail, Bloody tips, Behavior may not change
Treatment: Conservative: Treat with Aq.Salt at 1 tsp/gal. Increase water changes to 100% daily. Replace accurate amount of salt following water changes. Add Stress Coat to help repair tissue. If there is little to no improvement within the first 5 days, you can increase the salt dosage gradually to 2tsp/gal but do not continue any salt treatments past 10 days. Medication: If Conservative treatment is ineffective use API Tetracycline, API Fungus Cure, API Triple Sulfa, OR API Erythromycin. Also add Stress Coat to help regrowth. Continue until fins/tail stop receding and start showing some new growth.
And the head.... is that white fuzzy/furry/cottony patches on his head? (It's a bit blurry)
But you can read about Betta fish disease and treatments here:
i change his water all the time.....literally, plus it is filtered i use kordon water conditioner each time. i did a 100% change last night..... changed filter but didnt rinse gravels or anything to keep some good bacteria