Boyfriend guardianship obligations?

LaCipota
My boyfriend & I are both in our mid 20s, together 2.5 years. His mother sadly passed away February. I've tried to be really supportive, stayed at his place more often while working & studying myself. So it's now him, 12 year old (half) sister & his step-dad (the sister's biological dad) living together.

My boyfriend's plan is to get a home loan with the life insurance & move the family closer to the city. My boyfriend is now his (half) sister's legal guardian because years back, apparently the step dad accepted to marry someone for money/their citizenship-I'm unclear as to whether it's still relevant/will be rectified. So on paper no dad was ever listed despite living with them since her birth.

My boyfriend & I were having a conversation about the house he is pursuing - of which I've been understanding. The conv steered towards how big his mortgage would be if he went for a large house & suggested maybe it doesn't need to be because it might impact our budget by the time he & I want to build together (potentially 4 years ahead). Then he stated that his sister would potentially live with us "if she preferred" & he would 'like to keep an extra room for her'. I told him that I didn't understand why that would be necessary since she has her dad; why would it be an 'option' if he IS around and isn't handicapped or anything. My boyfriend then said, well what if he goes away for some reason or starts a new family (he's in his 50s?). He randomly hypothesised if his stepdad just decided to leave/since he's not as "hands on" she might be 'more comfortable' with us.

Well, I got quite upset with this type of suggestion & when I was trying express my concern he raised his voice "it doesn't matter what you say, I just know that she has to be with me until she is ready to go". I was in disbelief & became upset. Do I have a right to be? I've been trying so hard to be there for him, even inviting his sis out & to my family outings. It's not like she would be abandoned.
Boyfriend guardianship obligations?
2 Opinion