My wheelbarrow has 2 front wheels, and is plastic. It's less apt to tip, and lightweight. I bought it at the local hardware store.

I don't have Parkinson's, so perhaps someone more knowledgeable than I would give you a different answer, but my suggestion is to be going through a gardening catalogue sometime when you're around him, and "discover" both types of wheelbarrows.Say something like "Oh, this is neat" and "Oh, this is something different!"

Show him the pictures of both kinds, then run down to the hardware or gardening centre and get him the kind he thinks is better.

I'll post a link to what I have, scroll down to Lawn and Garden Cart

Here is a link that might be useful: Lawn and garden cart

i think what is important is to have 4 points of balance. so for instance, 2 wheels and then 2 points on the back where the wheelbarrow rests. anytime i see 3 points of contact/balance i think the wheelbarrow will be tippier. a long way of saying that the nubarrow has 3 points. the vermont cart and the smart cart have 4.

Here is a link that might be useful: compare wheelbarrows chart