My grandmother likes sweet. ✓
Because as we gets older like grandma our body won't have sweets anymore.
So, my grandmother likes sweets very much. ✓

2nd sentence:
Because, as we gets older like grandma our body won't have sweets anymore.
correction: As we get older like a grandma our body won't have sugar anymore.

#1 There is a circumstance in which we can start a sentence with ?because? and not be violating any silly rules. If we start a clause with ?because?, then insert a comma, and then a second clause, then both of the clauses are in the same sentence and everyone is safe.

#2 As we get - subject verb agreement (Plural subject + no s verb)

#3 Let's use the appropriate words for making our sentences. example: sugar - sweet