brother is much more open, is basically the other half of her coin, her best friend, ride or die etc. they are originally from san fran, but willa moved to nyc for college and only recently moved back home. what he's been up to during that time is completely open.
for the husband, i do have a rough outline but most can be discussed and changed if you're interested. i was thinking he's a little bit older than her, doesn't have to be a MASSIVE gap though. they would have met a few years after she had her son and while she was living in nyc. at the time she was a freelance hairstylist and makeup artist trying to settle into her career and start her own indie perfume line but still a struggling single mom. i was thinking he was a photographer or something creative and they really fed off each other in a "muse" type relationship. their marriage was fueled by a lot of passion but fizzled out a bit in the last year (i was thinking because they started to resent the other for having their lives revolve around each other?) and they decided to either get divorced or separate (either is fine with me) and willa moved her and her son home to san fran to be closer to her family and her son's father. as for why he also moved, they could have either decided to mutually move there together prior to the divorce or could be due to his close relationship with her son. it's mostly the bare bones, so i'm really up for discussing further if you wanted to make something fit.
both would include a line with her son's dad ~dcostillo. and both probably don't have the highest opinion of him. he would have been an extremely close friend of her brother's though when they were younger. he introduced them and declan and the brother would have gone to school together. for the husband, he's probably mostly a nuisance.