I have Knee/neck problems but father is old and wants help with Hard work, what to do?

I'm 26 my father is 56 and he's a gardener. sometimes my father wants me to go and help him to do hard work like trimming, or picking up branches and dumping them onto a truck..or other stuff required in gardening projects. I feel bad because yes i know, and i want to help my father but i have extreme knee problems, and neck problems. just recently i had a neck injury that left me without being able to move my neck for a few weeks, i still can't fully turn it , it's better but not yet.That injury was caused by the same lifting of branches kind of job, and due to me not being able to bend my knees, lifting heavy thingsis why i'm getting hurt alot . Anyways, since i'm young my father doesn't think i have anything..i've told my parents, and i even limp so much and i can't walk some days.. but he thinks i'm strong and able.I don't know what to do...i told him, "i can't" but he gets mad and disappointed..and then i feel bad he has to do it on his own.

Be upfront about it with you dad. Tell him that you DO have problems and that you're sorry but you can't be helping him in the garden because you don't want to make it worse. If he gets mad or upset that's on him.

I would get a doctor's note. Perhaps then they would trust the official word of a physician that states what restrictions you have.

See the Dr. and get an excuse slip for limited duty.