I have a question conserning my dogs health?

He is 3/4 boarder collie and 1/4 rot wieler. A policeman friend of mine asked me to care for him as his owner was going to jail! I was 48 then and was a kitty girl and the 2 that were with me at the time seemed to want to ask if I had lost my mind! Now it's 9yrs later and both kittys are gone and it's me and Napolean...he misses the kitty's as much as me! Anyway, I have NO IDEA how old he is but i'm pretty sure he he is at the very least 12 or 13+ years old. I feed him well and give him fresh water almost everytime I walk by his bowl, 7 to 10 times a day, ect, ect...As for a vet, I honestly don't have the $...Now that i've babbled on I will get to the problem. My nephew left a work tool here, it is about 5 feet tall, solid steel and just guessing weighs between 60 to 70lbs. So napolean wanted out and as he ran by his foot slipped and the pole hit him on his back. It was horrible but i rubbed lightly, a little ice and alot of attention, he seemed a little sore but okay, Then today, 3 day's later my nephew comes to get the steel tool and heads down the hall to the bathroom and didn't see napolean so he tripped and fell on him (I would run away from home at that point!!!) Now he's some what listlus and I know very sore and stiff, can I give him, say 1/2 of a prescription 800mg ibuprofen or the entire pill? Or I also have a low dose 81mg asprin that one would take if they had to take one a day for a bad heart...Does anyone know or have any other ideas? I know vet's need $ also but it seems they only care until they learn you are broke. Sorry I went on and on but I never dreamed I would say these words, This dog, Napolean is the best thing that ever happened to me so, I could use all good thoughts and any good advice... THANK YOU