Pram and wheelchair?

I'm going with my grandmother to an appointment tomorrow, but I'm unsure on how to physically manage with her wheelchair plus my son's pram. I used to take her to all of her appointments but stopped when I had the baby, and I was talking to her yesterday and found out she'd been going alone for some months because my aunty had become unable to to go with her a little while back, and I just felt awful. Not my fault I know, but I want to be there for her and she was really pleased that I'd offered to help too as she hates going by herself.

My son is 16m and walking pretty well but I don't trust him to just walk along side her chair. Anyone have any experience with this or any advice/ideas how it could work? I'm determined that it can!