update sister in law abortion

i'm really upset because my sister in law texted my husband tonight asking for a ride to an abortion clinic in two weeks on tuesday. first off we didn't even know she was pregnant so it was definitely news. second that happens to be my birthday and she knows we have plans so i'm not sure why she made the appointment for that day. but the main reason i'm upset is because i understand abortion and i'm for it when it's needed. but she knows we have been trying for almost a year to get pregnant and asking him that just made me so sad. she has twins that are almost two and they were an accident and now she's accidentally pregnant again andus not being able to have a baby has been hard. to think she has accidentally gotten pregnant twice and i can't just makes me really sad. i guess i just needed a safe place to vent. anyways thanks for reading. 
Update:
first i want to say thank you for all of the support i have recieved. i'm not gonna lie it was hard reading some of the people's comments saying i was too sensitive and it wasn't my place. but to the point..
My husband and I did decide to offer to adopt the baby and she is thinking about it. she told us she really doesn't want to get an abortion especially knowing our struggles but she personally can't do it right now with another baby. we told her we respect whatever choice she makes but just wanted her to know the offer was there.
as for the whole birthday thing, we won't even be in town that day and she knew that because our dog is staying at her house and i understand appointments are few and far between but that was more of a misunderstanding and wasn't really anything i was actually mad about i was just more confused and concerned that we have had this planned for a couple months and it wasn't a cheap trip so it worried me that we couldn't do it. lastly, the comments that say it's not my business and such, she made it my business when she told my husband and me. again, i support whatever decision she makes and she knows that so i'm not sure why i got so much hate, because i thought i made that clear in my original post but since i didn't i just want to reiterate that it's her choice and i will support her no matter what, but it's still extremely hard since we haven't been able to carry to term.