I need a family lawer

I am a beneficiary to my late Mothers estate. There are 5 Siblings in total that the estate is being shared between. My two Brothers are joint executors. There was no will in place so letters of administration were applied for & granted on the 28th April 2021. My late Mothers house sold in September 2021. All money, minus fees entered the executors solicitors account 8th October 2021. A seperate conveyancing solicitor did the conveyancing on the house sale - & their charge taken from the proceeds. Therefore the proceeds that entered the executors solicitors account formed part of the estate, along with the balance of a bank account held by my late Mother. The property that was sold had my Sisters name on the property deeds as the joint owner. My late Father was the other owner who passed away over 20 years ago. My late Mother & my Brother (one of the executors) was stated as beneficiaries on the deeds. However my Sister has since relinquished her claim on the house & allowed the solicitor to draw up a family agreement in which all family members are to receive an equal 1/5 share of the balance of the estate. At the end of my Mothers life, she came to stay with us for a period of 100 days. At the time Covid was rampant & we could not bring ourselves to allow her to go into a residential care home. My Sister at the time was my Mothers main carer but could not commit to carying out the full time 'live in' care that was required. Under discussion, myself, my Mother & my Sister agreed that she come to us. Her health declined & it was decided that due to the level of care required by both myself & my wife payment was necessary - as neither of us could work. This was in full agreement with my Mother & Sister. Therefore a payment of £850 per week was paid for a period of 12 weeks & then a payment of £500 per week in the last 2 remaining weeks of her life. My Mother was in full agreement with all of the details, her mental capacity was not impaired. However no lasting Power of attorney was in place. However these were her wishes - as she did not want to go into Hospital or a Residential Care home. This care, allowed all family members to have access to her in the last few weeks of her life. We did not discuss these arrangements with the other family members. In the last week of my Mothers life, my Brother (one of the executors) found out about the care costs & was very angry about all of the situation. He made accusations that these costs were illegal & excessive., which he has tried to pursue with the solicitor. The solicitor has made his investigations & has agreed that these were done 'above board'. However both executors are still not agreeable with this outcome. The Solicitor has finally sent through his statement of account. We have been charged a bill of £7005 for his services. I feel this is excessive given that this excludes conveyancing. I have requested a breakdown of his costs. His bill consists of lots of items charged on an hourly basis & two large entries (almost half the bill) which I presume are a percentage fee. There is also a fee from my Brother of approx £3500 - which I have requested clarification, but neither the Solicitor or my Brothers are clarifying all details requested. Despite requesting clarification, I have agreed to the statement as I just want the matter bringing to a close. The solicitor has made it clear that I am not his client & that any involment with me is out of courtesy. He now wants me to sign a form agreeing with the account summary & relinquishing the executors of all responsibility. I am refusing to do this, out of principle - as I have already given him written authority twice already. His letter to me is very harsh & straight talking - not what you would expect to write to a grieving relative. He is also now saying that failing to sign the form will result in the estate being part shared out to the other members in agreement. I therefore need legal advice on what rights I have.