Hmm, it's very very difficult when he refuses to see a doctor. Just as a work around,, do you think it would help if you bought another meter and told your dad that a friend had lent it to you? Your profile says you are T2 (though I don't know if that refers to your dad). Maybe you could lend him your own meter? Just a few tests would give so much information to take to a medical professional.
You are obviously a very caring daughter who is doing everything she can for her dad, but ultimately you are not responsible for his refusal to get help. Do you have other family members or family friends who could help try to change his mind?
Lots of virtual hugs. Good luck.