I have 5 DSD and one DD. DSD5 is 13 and so rude. No sn's but refuses to say thank you. I could give years of examples. The worst to me is when my sister on benefits and five children of her own gave dsd5 a birthday gift she pocketed the cash and refused to say thank you. DP and I have gone around on this too many times while yes he agrees with me he does fuck all about it. FWIW this is her behavior with all not just my family. I bought her a few trinkets on a trip we took her mother didn't allow her to go on. No thank you so I took them back. We are going on a trip this weekend. AIBU unreasonable to tell her father he is to pay all expensive for her during said trip. Food trinkets etc.