sins of father quest final boss phase 2

Hello,
Anyone who had finished the quest'sins of father' in OSRS please help.

Im having problems on the final boss phase 2. I cant successfully kill the vampire and dodge the lighting.Yes Ive watched youtube videos and they did same like me . But I just cant make it.Every time I move to another tile and then the black circle is there and then Im dead.

I have the netizot helmet and kailr legs and dragon boots etc. please anyone who did at least over one time tell me how to pass this? I could pay 10M if you are an experenced quester explaining this.

Thanks.

 

I don't understand how people struggle with this boss lol, just walk away and let the lightning appear then attack?

also whats your stats?