My perspective on this, let’s start with the first point hubby and the wife’s relationship. I am going to touch on the main branch (main point) and hopefully you will understand the smaller branches to the main branch, so I don’t have to get into details. Never make husband the “wife” in the relationship, let nature take its course and let him be the man in the relationship. Nature is above all. Some “men” can adapt and will take the wife’s role in the relationship, not a great idea. Might as well marry a girl and adopt its legal now.
Second point wife’s relationship with the siblings, that you pointed out. I say treat them like potential friends, relationships run on you do little things for me and I do little things for you, favours. Example my mum is not in and I can’t make a cuppa, my bhabi makes a cuppa for me. A small favour, the next day I am buying a gift for mum, sister, and I will get something for bhabi as well. Or the next day I am about to go out with mates, and bhabi asks me to drop at her friends or at a parlour and I do it without making her ask twice and make my mates wait.
Third point and may be the most important one the mother/father in law, even though they main branch is the same meaning every family is a kinda similar( there are bad and good sides to every family) but still there are small stuff that make almost every family unique, the small branches. Different situations, different life experiences, that current period, history. Take everything into account, but above all and when things are good or bad you put (treating our elders with respect) label on the back of your perspective or how you going to react to a certain situation or do things or make opinions etc. Treat them with respect our elders deserve and how we were taught to respect our elders by our parents, society, and our culture. Then continue to take a decision, make opinions, and deal with a certain situation come what may...The first couple years are difficult if you ask any of our mums, majority will say that and then they say it made them who they are. On the flip side, Women go through so much already, 2 or 3 years of “hardships” should be a walk in the park for them. On a more serious note try their best to keep the family intact, because little things can turn into bigger problems for life, so hopefully then there are no regrets when one is older and more mature. Above all family is everything.
My two cents.