How should I go about asking someone's family if I can come visit/spend time with a friend's urn?

I don’t even know how to word this question.. sorry.

My best friend committed suicide about 2½ years ago.
I just found a letter from him that I never read.
He wrote it 2 months before he died and instructed me not to read it until my birthday.
He died before my birthday, so I put the letter in a box and forgot about it because I was still grieving.

I haven’t been able to bring myself to contact his mom and check in for a while because I’m not sure what to say.

Now, I want to go visit with her, and spend some time with his urn yeah, talking to him still helps me, don’t judge me

I’m not sure what to say when I call her…
Help?