How do I respond to my Uncle In Law telling me to wait to buy what baby needs?

[MeriBetiBahutSoniHain]

My Uncle in Law is from India. So is my husband. My Uncle in Law keeps telling me not to buy anything until the baby is born. I told him you MUST have some things before the baby gets here. And that I don't need the extra stress and tension of dealing with everything alongside not having everything. He keeps saying "I'll take care of it when the baby comes". I have money. I told him I am NOT Indian and that in the US, we take care of these things before the baby gets here. He was giving me such a hard time. Today he and his friend were hanging in the living room having the rare down time since they both are workaholics. I ended up buying a rocker that I knew was necessary for $3 from a rummage sale. At first he tried telling me not to buy anything yet, again. I then snapped at him and told him I had to deal with the stress, with the lack of sleep, with breastfeeding, and with getting things done while making sure the baby was safe. I told him I WAS going to buy everything necessary because I am an organizer and in order for me to feel at ease, peaceful, and stress free I needed to get things done. His friend interrupted and told him I am intelligent and doing right by getting it done. THEN he listened. How can I get him to understand that women in the US are not going to wait until the last minute for what can be done now in regards to pregnancy and babies? He's a great person most of the time. He keeps making sure I'm happy and he doesn't let me stress myself out physically. My husband and him will not let me work and they won't even let me pick up laundry. So in that way they are making sure I'm stress free. But when they talk out of their behinds, it is so nerve wracking that their efforts seem pointless. After having a final showdown today and having to raise my voice (I do that extremely rarely and when I do they know I mean business), he said "Ok, do what you need to do. I am just giving you my opinion and I am just trying to take care of it all" I pointed out that I had money and since he is supporting me while my husband is in India, the least I can do is to spend the money I have for myself on what I need for the baby. He finally got it. How can I respond to him in the future to avoid this tension? He's a know-it-all and gets stuck on that until he gets majorly challenged. He's a great person. Just hard headed and annoying at times.