Hello Victoria!
Welcome to planDisney, it's so nice to meet you! I can see you have quite a few questions, I'll do my best to help you with all of them.
First, I'm sorry to say that the
Disneyland Resort Rules prohibit trailer-like carts that are pushed or pulled. But I totally understand not wanting to carry everything all day. I highly recommend
renting a locker inside the park (you can open it as many times as you need to during the day) so that you can store your meals and belongings. It's also important to remember that backpacks or coolers larger than 24" long x 15" wide x 18" high (61 cm x 38 cm x 46 cm) are not allowed, and you cannot bring glass containers (except for baby food jars) or loose ice.
There are several
locations in the parks that offer Kosher meals. My wonderful fellow panelist
Jason has great recommendations for arranging Kosher meals at the parks! You can also
send an email to contact a Cast Member who can help you with Kosher meal recommendations. You mentioned Plaza Inn specifically, however that location is not currently listed as an option for Kosher meals. I would recommend
Red Rose Taverne instead!
A bit of good news for you:
cane chair and seat-walker mobility aids are permitted in the parks. I hope that helps make your brother's visit a bit more comfortable! Regular folding and camp chairs are not allowed, so make sure that you don't bring those for your visit.
I know planning for specific circumstances can take a little extra magic, but I hope that this information helps! I'm wishing you and your brother a truly magical day in the parks, Victoria.
Keep moving forward!
Amanda