Future lone rat

Question
He isn't lone yet and I hope his companion is there for a long time however in the event of one of them dying, what do I do?
I started with four but in the last couple of months they have both passed away and now Im worried that I'm going to have a lone rat.
I personally want to rescue two baby boys that are at the rat rescue near me at the moment but my mum said I have to wait till I start college (erm whole 8 weeks till I start? Best time to get them would be now? No?).
She says that having one on its own will be fine as long as I get it out more often but she has done no research into this at all! I did so much before I got them! She doesn't understand that I won't be their pillow and grooming buddy will I! I there are a little over 2 years. They are both males.
If one does pass would it be best for me to give the other to a friend of mine that rescues and is very knowledgeable about ratties.
I don't know what to do and I am really angry at her for being so inconsiderate towards the rats even though she says she loves them!
So, what do you think I should do?

There are 2 at the rescue now, so it wouldn't be an adjustment when one died because the others would already be there.  I really hate the thought of him all alone ):

I think It would be like taking someone from there family, letting them see one person everyday for 8 hours or so. This would be fine if they were brought up like that but if they have had constant company their whole lives it would be devastating. Would it be better ti give him to my friend if this happened and I wasn't allowed anymore?

Answer
Truthfully, its difficult to introduce adult males to other males, and if they are young, the adult may hurt it if not kill it if he decides he is threatened by them.  I have had many solo rats after they lose their cagemates and unless they really start to act depressed, I dont want to stress them by bringing in new rats. Females are different though, most tend to accept other females readily at almost any age.