Have been lurking on this thread and would like to share my thoughts.
If i'd seen this post a few years back when my dcs were babies I would have sympathised with OP's friend. My advice now.......45 mins is way, way too long to leave such a tiny baby.
My ex sister in law lent me a famous controversial book on parenting.....at the time I thought it was the best thing since sliced bread, resulted in both dcs sleeping 12 hours through the night at 12 weeks as well as two or three hours during the day. Everyone told me how lucky I was. Actually looking back now it was the very worst thing I ever did. I didn't enjoy my dcs as babies, I just ploughed on consulting that fucking book every five minutes. The routines became so ingrained that even now (oldest dc is nearly 10) when I see mothers out at various times of the day I check my watch and start to think....ooooh that baby should be having a nap, at home, in a completely dark room, then I have to slap myself.....said mother pushing pram looks happy, content as does the baby. If I could turn the clock back I would, i would savour every precious cry, cuddle, comfort etc etc.
And now......after all that fucking routine, and plenty of sleep and contented babies, I feel overwhelming guilt that I didn't have the balls to do it my way, as nature intended.
It's only now that I can't bear to see my precious dcs cry, no matter what they've done, how much of a shit they've been, if they cry it eats at me and breaks my heart to the point I can't bear it and I have to comfort them. It's now that I should be firm and let them sulk in their bedrooms but I can't, they know it and as a result they manipulate their guilt ridden mummy :( . So who's made a rod for their own back now.......yours truly.
OP I know you can't show your friend this post, but if there is any way you can convince her not to let her baby cry for that long, please do it.
Sorry if this is long and a bit dramatic but I feel so very, very strongly now and I just wish I did it all differently.
ps I would like to shove that fucking book sideways up the author's childless fanny........sorry very crude of me but that's how I feel.